The relief corps was decent in 2020, with New York getting a dominant season from Edwin Diaz and strong work from Justin Wilson and Chasen Shreve.
With Familia under contract for the 2021 season at $11 million and Betances seeming likely to exercise his $6 million opt-in, the bullpen next season will likely not look radically different.
But with the potential departure of Wilson via free agency, uncertainty surrounding Robert Gsellman after a rough 2020 season that ended due to injury, and another unknown in Miguel Castro likely part of the 2021 group, New York will need some reinforcements from outside the organization.
The Mets will also need to hope that some of their live arms on the 40-man roster and in the upper levels of the minors will be able to offer some support.
What the Mets have going for them heading into 2021
Edwin Diaz and (potentially) an old friend.
Diaz, as many (including this writer) predicted, had a bounce back season in 2020, posting a 1.75 ERA and 1.24 WHIP with 50 strikeouts in 25.2 innings.
While it's understandable for some Mets fans to feel apprehensive about Diaz given what happened in 2019, it's clear that he turned the page in 2020. And he should be relied on to be a key piece in the back end of the bullpen in 2021, whether he's the full-time closer or the team goes closer-by-committee.
The old friend cited above is Seth Lugo, whose results in the rotation in a small sample this season were not great. While Lugo has been adamant about his desire to start and while he didn't get a ton of time to prove himself in the rotation in 2020, it would be in the Mets' best interest to shift him back to the bullpen, where he's been a shutdown arm who is able to provide multiple innings.
With Diaz and Lugo as the late-inning base, the Mets should often be able to use Familia, Betances, Castro, and others in much lower leverage spots.
But even though Betances will likely be on the team, it's hard to know what the Mets might get from him. His velocity was down again this season after a big drop from 2019 to 2018.
Free agent and internal options
Looking at internal options first, the Mets could potentially get a boost from Drew Smith, who will be a year removed from Tommy John surgery.
In addition to Smith, the Mets could turn to live arms including Franklyn Kilome (who struggled in his big league debut in 2020) and Ryley Gilliam. The 24-year-old Gilliam has not yet pitched in the majors, but he has late-inning potential and should be ready at some point in 2021.
Then there's Thomas Szapucki, who was dominant in the minors from 2015 to 2017 before undergoing Tommy John surgery. Szapucki, the No. 8 prospect in the Mets' system per MLB Pipeline, returned in 2019 and pitched very well while on an innings limit as he built up arm strength.
The wheels should be mostly off for Szapucki in 2021, though he almost certainly won't be able to handle the full workload of a starting pitcher. That could create an opening for him to break into the majors as a reliever, making him a potential left-handed option whose plus stuff could play up even more in the bullpen.
Turning to the free agent options, Liam Hendriks is the reliever who stands out. Beyond Hendriks are interesting but flawed options such as Alex Colome and Keone Kela, who dealt with a forearm issue that cost him most of the 2020 season.
So how exactly do the Mets fix the bullpen?
Unlike the situations in center field and behind the plate, where the Mets simply need one player at each spot (though finding those players won't be easy), the situation in the bullpen is murky and further complicated by the fact that the team is seemingly locked in to both Familia and Betances for 2021.
Could Familia and Betances have strong seasons in 2021? Sure, but the Mets can't rely on that. As noted above, they also can't rely much on Castro -- at least not yet.
Given the state of the bullpen, it seems like a no-brainer to move Lugo back there in order to add some much-needed certainty.
The Mets could also potentially get some value from the group consisting of Smith, Kilome, Gilliam, and Szapucki.
And then there's the free agent market.
While it's fun to imagine what prospective new owner Steve Cohen might do, he won't outbid the rest of the market for every top free agent -- nor should he.
That means -- depending on what the Mets do at catcher, in center field, and with the starting rotation -- fixing the bullpen might take a bit of creativity.
New York could sign Hendriks, giving them what could be a lethal three-headed monster of Hendriks, Diaz, and Lugo. And maybe they'll go that way if they don't land one or two of the other big fish of free agency. But adding Hendriks can't be expected.
Starting with this offseason, the Mets need to do a better job of building their bullpen from within and putting their pitchers in the best position to succeed. That means giving a long look to the internal options mentioned above, moving Lugo back to the bullpen (though he won't be thrilled) and picking their spots when it comes to free agency. If that's Hendriks, great. If it's a lower-level arm, so be it.
The free agent market for relievers is simply too volatile, as we've seen year after year. And the Mets need to slowly start putting themselves in a position to not have to rely on it.