3) Former NY Mets infielder Justin Turner can be traded by August 1
Easily the most frustrating former Met on this list is Justin Turner. The Mets had Turner from 2010-2013 before choosing to non-tender him in the 2013 offseason. He wound up in Los Angeles with the Dodgers and turned into a future star that would torment the Mets everytime he played them.
Turner's nine-year run with the Dodgers ended this past season as he signed a deal to join the Red Sox. Serving as Boston's primary DH he's had another solid campaign.
The Red Sox are in a bit of a difficult position. At 55-47, they're just 1.5 games back of the third Wild Card spot in the AL, but they aren't a guaranteed postseason contender.
According to Robert Murray of FanSided, Boston's deadline plan is to try and make moves that keep them competitive for this season while also keeping an eye on the future. This means not trading all of their key players, but moving on from free agents to be, like Adam Duvall. This could also be applied to Turner.
The 38-year-old signed a two-year deal worth $21.7 million this past offseason, but the second year of the deal is a player option. There's a good chance Turner opts out of the $13.4 million he's owed and seeks a richer deal this offseason. That makes him a likely free agent as well.
It's unclear whether Turner is available considering he's one of Boston's best players, but if he does become available, he'd be a highly sought after trade piece that could help any contender.