Jul 14, 2013; Flushing, NY, USA; New York Mets former player Mike Piazza hits during the 2013 All Star Legends and Celebrity softball game at Citi Field. Mandatory Credit: Brad Penner-USA TODAY Sports

Mike Piazza took PEDs? Where's the Evidence?

Former Mets catcher Mike Piazza is a big, muscly guy who hit a lot of home runs. A couple of sources have noted that he, over the course of his career, had issues with back acne (a symptom typical of, but not exclusive to steroid users).

He also played in the 1990′s / early aughts. So he did steroids, right?

Come on, he had to.

Everyone was doing it.

How else did he get that kind of power?


…Maybe he was just good at hitting baseballs?


Among MLB hitters in the liveball era (since 1920), Mike Piazza is probably one of the  best power hitters. He ranks 45th (.237) in isolated power (ISO) and 47th (427) in home runs. He was also a good hitter in general – his .308 batting average ranks 55th. What makes most of this astounding is that he accomplished the majority of his offensive resume as a catcher – the ISO and home run marks are both MLB records for the position.

But some argue these numbers are tainted. They say Piazza took performance enhancing drugs illegally and/or immorally, and that such drugs padded his numbers. Did they?

Well, for that to be true, there needs to be some evidence that his numbers were “enhanced”. Ostensibly, home run power wouldn’t be the only benefit of performance enhancing drugs, but no one’s ever argued about Piazza’s ability to hit for average (nor his very good plate discipline) being tainted. It’s the dingers, because PEDs = dingers & strikeouts.

The simplest way to measure power is looking at ISO. It’s calculated by subtracting slugging percentage from batting average, and thus measures total bases beyond first per at bat. Singles are worth 0, doubles 1, triples 2, home runs 3. Add that all up, divide by at bats, and you’ve got a number representing how much power a guy hits for. For reference, the MLB (non-pitcher) average hovers around .160.

So let’s look at Piazza’s ISO by season* compared to his career overall. I’m including his minor league numbers, but they’ve been separated into individual levels instead of seasons. I also omitted his 1992 major league stats as he only accumulated 79 plate appearances. Put it all together, and you get something vaguely resembling this:

Piazza ISO

*Seasons listed by player’s age on January 1st of calendar year

For the most part, you have a fairly smooth, clear career arc: steady improvement heading into a solid prime, and steady decline. Oh wait, that’s not so steady. How do you explain his age-33 season, where his ISO dipped from .264 to .197? How do you justify such a precipitous decline in 2003 – the year after androstenedione was banned by the MLB?

Sep 29, 2013; New York, NY, USA; New York Mets former catcher Mike Piazza speaks during his induction into the Mets Hall of Fame prior to the game against the Milwaukee Brewers at Citi Field. Mandatory Credit: Brad Penner-USA TODAY Sports

Piazza only played in only 68 games that season (his fewest since a September 1992 call-up). He was out from mid-May to mid-August with a “grim” groin injury. It was expected that he would miss the season; at that time his slashline resembled .333/.462/.613 – a healthy .280 ISO entirely in line with his career to that point. In his first 15 games back – up to the end of August, he hit .261/.426/.522 – an ISO of .261 that still met expectations. He struggled badly in September, failing to hit a home run and posting an OPS of only .547.

2004 saw a similar pattern, though Piazza avoided the disabled list. He hit an entirely Piazza-esque .297/.388/.506 with 16 home runs. Again, he struggled mightily in the second half – .200/.305/.310 with only 4 dingers.

At age 36 in 2005, Mike experienced a small bounce back. There’s a decent reason for it too: the Mets started taking it easy on him. As the year went on, Piazza’s production increased as his workload decreased – he posted a .169 ISO in 75 first half games (297 PA), and a .272 ISO in 38 second half games (145 PA). The Padres followed that pattern and got a successful 2006 out of Piazza. Keeping him fresh allowed him to experience his best power season in a few years – his highest ISO and home run total since 2002.

Occam’s razor suggests that the simplest hypothesis is often the correct one. Piazza’s decline was somewhat accelerated by injury. But his ability to hit for power was largely maintained, especially when the load of catching regularly was reduced. Could him quitting ‘roids be an explanation for his decline? Perhaps if we actually had an idea how to quantify the effect of performance enhancing drugs, yeah. But it’s most likely the result of an aging catcher who averaged 137 games behind the plate over 10 seasons with a significant, career-altering groin injury.

But that’s not enough. Comparing him to other big power hitters of the generation, we can somewhat contextualize Piazza’s power in the steroid era. Below is a chart listing ISO by age (like the one above) that includes multiple big power hitters of the 1990′s: Barry Bonds, Mark McGwire, Sammy Sosa, Jason Giambi, Craig Biggio. For reference, David Wright is also included.

Multiple ISO

*See above chart for season explanation

What jumps out is that Mike Piazza’s “power” stayed dramatically more consistent than the other big power hitters of his day. The wild spikes and dramatic variations that peppered the careers of Mark McGwire and Jason Giambi are absent from Piazza’s resume, as are the superhuman peaks of Barry Bonds and Sammy Sosa. 31 seasons shown represent an ISO above .300 – none by Mike. More than any other player on the graph (save for, perhaps, fellow victim of the era Craig Biggio), Mike Piazza’s career arc most represents what you’d expect visually from a player’s career; his numbers improved somewhat steadily into his early 30′s, and would have declined smoothly were it not for a significant injury and the wear and tear of playing catcher every day into the second half of his 30′s.

Mike Piazza was a big, muscle-y guy who hit home runs in the 1990′s. He also showed very good disclipline and even stole five bases once. He admitted to taking androstenedione before it was banned in 2003. There’s a corresponding decline, but it’s neither as dramatic nor as inexplicable as some of his counterparts. Unless you assume that either

(A) Mike Piazza was consistently taking performance enhancing drugs and continued to after 2002


(B) Performance Enhancing Drugs don’t tangibly enhance a player’s performance

there’s not a lot to suggest that Piazza’s career was tainted by illegal PEDs. If you believe he stopped in 2002, it’s hard to explain the sustained stretches of Piazza-in-his-prime dominance he displayed in 2003-06. If you believe that the PEDs kept him healthy, you’re fighting what’s perhaps a more difficult argument in trying to morally qualify elective medicine. What would make it materially different than the amphetamines players – like Hank Aaron – took in previous decades for the specific purpose of easing the rigors of a 162-game season?

I’m not going to get into the actual steroid debate here**, because I don’t think I have to. The argument championed by blogger-by-a-different-name Murray Chass is that the drugs boosted his power and were responsible for making him into the greatest hitting catcher of all time. It fits the narrative. He’s a big, muscle-y home run hitter – a 62nd round pick no less – who put up Hall of Fame numbers. He was a nobody!

But it’s an uphill battle to suggest that with disappearing bacne and a single testimonial from a player on a different team are your exhibits A and B. There’s no smoking gun, only smoke.

The numbers just don’t support it. “Eye tests” and “gut feelings” aside, the numbers are what matter here. No one got into the Hall of Fame just looking the part (seriously, google Babe Ruth).

So where’s the real evidence?

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** In full disclosure, I believe that players in the “Steroid Era” should be in the Hall of Fame regardless. Aside from the fact that we make significant moral assumptions about past players, we’re pretending that an entire decade of baseball history didn’t happen. We all cheered ignorantly (perhaps feigned ignorance) when McGwire and Sosa’s home run chase effectively saved baseball. We enjoyed the Bash Brothers in Oakland. We also fail, at times, to recognize the magnitude of a player’s career ending, and the fact that the majority of those we label cheaters are players fighting to stay in the show and not those who are gunning down records. 

When Warner Brothers released the Looney Tunes DVD collections in 2003 (fitting given the topic at hand), they included the following disclaimer:

“The cartoons you are about to see are products of their time. They may depict some of the ethnic and racial prejudices that were commonplace in American society. These depictions were wrong then and are wrong today. While the following does not represent the Warner Bros. view of today’s society, these cartoons are being presented as they were originally created because to do otherwise would be the same as claiming these prejudices never existed.”

We shouldn’t be trying to sweep the era under the rug. While we shouldn’t necessarily be in the business of honoring ill-gotten achievements, we have no business ham-fistedly policing the bygone product of our tacit excitement and greed. Tell your children that some players made some morally-questionable decisions, and tell them about the fun we all had watching it happen. They’ll probably learn a better lesson from us recognizing the struggle to capture ever-fleeting greatness – which is perhaps the essence of sport – than from us batting a blind eye to those who make morally-reprehensible ones that we ignore because driving drunk or domestic violence have nothing to do with sockin’ dingers.

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Tags: Baseball Hall Of Fame Mike Piazza New York Mets

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  • BronxMets

    REally you want to go there. You honestly don’t think he did them? Serious? Hey why not look at his minor league numbers. Oh yeh that’s right because it will blow your entire argument out of the water. You can convince yourself of anything you want if you are not willing to look at it objectively. But anyway proof would be that he had a clean test every year of his career. AS with the other players he chose not to do it so we are left to think for ourselves. MIke PIazza took steroids. There is no other conclusion you can gather for his success. Oh yeh you left out his college years too.

    • Sam

      Really? Because he hit a home run once every 23 at bats in the minors.

    • BronxMets

      really like wow like cool like yeh  like what a stupid comeback. like did you not understand what I said? did I talk about his avg his entire time in the minors is that what I was talking about that’s what you got out of that? Pay attention.

    • Throwin Chedd

      You argue like a child.

    • Sam

      Really like .296 career batting average in the minors like wow

    • BronxMets

      OK FLaash card time pay attention class:

      1989 1 hr every 24.75 PA
      1990 1 hr every 45.3 PA
      1991 1 hr every 15.4

      WOW How did that happen…………hmm let me see…could it could it be could it just be……

    • Sam

      1992 1 hr every 23 PA practically going backwards to his 1989 form.

    • BronxMets

      went to AAA nice try…………..

    • WalterPeck

      Dramatic improvements, particularly in the minor leagues, don’t necessarily indicate the player is cheating. It can just as easily mean they figured out their swing and plate approach. Take a look at Griffey’s stats from early in his Major League career:

      1989 – 1 hr every 31.6 PA
      1990 – 1 hr every 30.2 PA
      1991 – 1 hr every 28.7 PA
      1992 – 1 hr every 22.8 PA
      1993 – 1 hr every 15.3 PA

      I think we can all agree if any home run hitter of the Juiced Era was clean, it was Griffey, and he experienced a similar rapid change in his power production at a more difficult level of competition.

    • BronxMets

      ok now lets stay on topic OK pay attention now. the writer said Piazza NEVER had a significant change. I am simply showing that is not true. if you snotnose bloggers would take 2 mins to actually read and not turn into little hormonal 13 year old girls you might be able to find a job.

    • Flatbush0460

      Dude, your hypothesis has been debunked. Take it like a man and admit you were wrong. Someone might have a modicum of respect for you at that point, but I doubt it. My guess is you’re either a whiny Yankees fan, or a sniveling Philthy fan. In either case you’ve just been exposed, deal with it, and get lost

  • Throwin Chedd

    I love Piazza and I always will. I truly got into baseball just as Piazza began playing for the Mets. He’ll always be my favorite baseball player of all time.
    That said, there’s no doubt in my mind that his career was aided by PED’s. I won’t even apologize for saying it because it shouldn’t offend anyone who truly follows baseball. He was a product of his era and capitalized on the resources at his disposal.
    I don’t have proof that he did and I don’t care. I know how to read statistics and analyze trends. I also remember how much of a tank he was. And I also remember how effortlessly the guy consistently popped opposite field bombs like he was pulling it. Guys today just aren’t doing with Piazza and so many of the hitters in that era once did.
    Still love ya Mikey, you’ll get in one day.

    • Sam

      Appreciate the honesty not trying to bring up a ton of bs

    • Throwin Chedd

      And for the record, my comment below was not directed at you. LGM.

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  • Larry Littlefield

    The arc of Pizza’s career is very similar to Johnny Bench, except that Bench caught on sooner and declined sooner by a few years of age.

    • Dan Haefeli

      Aside from Bench’s .159 ISO in 1976, they’re remarkably similar career arcs.

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  • Joe Schmell

    Did you read his book? He mentions taking Andro which is a PED, the same one McGuire took

    • Dan Haefeli

      In the article I mention the fact that he admitted to taking Androstendione. Prior to 2002 Andro wasn’t a banned substance, and by all accounts he stopped using it when it was banned.

      We don’t actually know what Andro’s impacts would be on a baseball player’s performance thanks to a lack of research/data, but in the context of discussion it shouldn’t be considered a “PED” unless someone’s asserting that he continued to take it.

      Infinite substances are taken to enhance performance, like caffeine or protein, that are completely legal. For the time that Andro wasn’t banned, there shouldn’t be any moral/ethical consideration. Prior to 2003, it’s just a baseball player taking a legal over-the-counter supplement.

    • joeythew

      McGwire took more than Andro he took steroids, too. No evidence Piazza took steroids – big difference. Plus Andro was an over the counter supplement sold at GNC that was allowed by MLB through 2001. Piazza did nothing wrong. Fay Vincent, the MLB Commissioner, banned the use of steroids in 1991 – in addition to them being illegal without a prescription throughout the land they were also illegal to use by a MLB player. McGwire broke the law and the rules of MLB. Piazza did not.

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