4. Mets pitcher Alex Claudio
Alex Claudio is another veteran southpaw who the Mets signed to a minor league deal. As stated earlier, this bullpen does not have a set lefty to make the team. I believe Shreve is the most likely one to make it, but Claudio has a chance to make the team as well, even if Shreve does.
Even though the Mets operated with just one lefty in Aaron Loup for a majority of the season last year, most bullpens usually have two lefties.
Claudio was not very effective last season with the Angels, posting a 5.51 ERA in 41 appearances. He wasn't particularly good against left handed hitters either, as they slashed .275/.333/.522 with four home runs in 75 plate appearances against Claudio.
However, Claudio has been effective against the lefties in his career. They have just a .212/.258/.339 slash line in 562 at bats against him. In a division with so many quality left handed hitters, the Mets might opt to use two lefties.
I personally wouldn't choose to have Claudio start the season on the major league team, but it's very possible that it does happen.