4. Collin McHugh
Of the relievers left, I believe that former Met Collin McHugh is the best of the bunch. I believe the Mets would benefit from a lefty but they could also benefit from adding on another quality arm to the 'pen.
McHugh is coming off of his best year in the MLB which saw him go 6-1 with a 1.55 ERA in 37 appearances. This came after he opted out of the 2020 shortened season.
McHugh was used in a variety of different roles for the Rays. He opened games seven times for them. He pitched in the middle innings to provide innings. He also pitched late in games when needed. McHugh was used in all kinds of situations and I think he could benefit in a similar role with the Mets.
If Carlos Carrasco still can't pitch in the first inning for some reason, McHugh has plenty of experience starting and opening games, he can do that for the Mets from time to time. He can also give them length if need be. McHugh threw 64 innings in his 37 appearances this season. He went as much as three innings in an outing five times.
If everyone in the bullpen is rested McHugh can come in and pitch a clean inning if need be. If guys are rested, McHugh can give the Mets a three inning outing to give others a breather.
McHugh can be relied upon against both hands as he held lefties to a .163/.230/.213 slash line this season. He was actually more effective against lefties than righties.
You can never have enough good relievers and the Mets would benefit greatly by giving him a second shot with the organization.