Once the Mets' three-year deal with free agent OF/1B Jay Bruce is final -- which may not be until next week -- they will have to clear a spot on the already-full 40-man roster for him.
The Mets recently added minor league RHPs Tyler Bashlor (who struck out 84 batters in 49.2 innings last season between High-A St. Lucie and Double-A Binghamton) and Gerson Bautista (who they acquired from the Red Sox last season in the Addison Reed trade) to the 40-man. So it's a safe bet the two of them are safe.
And unless the Mets are dropping a pitcher such as Rafael Montero or Chris Flexen -- which they absolutely should not be doing given their lack of starting pitching depth -- it's hard to see a pitcher being removed from the roster at this point.
The team is thin at catcher and in the outfield, so the most logical spot to subtract from is the infield, which means infielder Matt Reynolds might be the player most in danger of losing his spot on the roster.
Aside from the expected starters -- Asdrubal Cabrera, Amed Rosario, and Dominic Smith -- the Mets also have infielders Gavin Cecchini, Luis Guillorme, Wilmer Flores, and T.J. Rivera (who is recovering from Tommy John surgery) on the roster. That makes the 27-year-old Reynolds, who has hit just .228/.300/.351 with four HR in 115 games in 2016 and 2017, the most logical odd man out.