For five seasons, McCann was a well below average MLB hitter (76 OPS+) on a very bad Detroit Tigers baseball team. The last two seasons, while playing for the Chicago White Sox, he has been more productive, culminating with an American League All Star selection in 2019. In the truncated 2020 season, he provided a career best 144 OPS+, though it was only over 111 plate appearances.
For those that may not want to pay the extra money for JT Realmuto, McCann is a reasonable alternative. He is, however, older than Realmuto; he will turn 31 three months after Realmuto turns 30. Realmuto is arguably as good of a defensive catcher as McCann, especially using stats like defensive runs saved (Realmuto -4, McCann -1) and percentage when it comes to throwing out base stealers (both have thrown out 36% for their career). Obviously, Realmuto brings more to the table as an offensive player. Regardless of what the Mets (or any team that signs him this offseason) do, he will bat somewhere between 2nd and 5th in the lineup. In an offseason where money is not expected to hinder the Mets, in my opinion, they should sign the better catcher.
Lets say McCann signs with the Mets. This could lead to what may be an underwhelming offseason for the team. Expectations are high because for the first time in the free agent era, the Mets are expected to be extremely aggressive in free agency without any financial constraints to hold them back. Offering a four year deal is insane, in my opinion, and could lead to other overpays for second tier-type players. In addition, not signing Realmuto will increase the likelihood he ends up in either Philadelphia or Washington.
Maybe the Mets could pivot to Trevor Bauer. But what if Bauer decides he wants to pitch elsewhere and does not sign with the Mets even if they offer him the most lucrative deal? Fans then get to sit and watch the introductory press conferences for both Realmuto and Bauer as they get set to join their new teams. George Springer would be a solid signing. But what happens if the Toronto Blue Jays have him set as their top free agent target and top or match the Mets best offer? They can trade for Francisco Lindor. But what happens if Lindor seems most likely to be interested in signing long term with either the Yankees or Dodgers and the amount of money offered in an extension is not enough to convince him to stay in Flushing long term? That would probably be a deterrent to any deal the Mets could make for Lindor with the Cleveland Indians.
So, imagine... Not signing Realmuto, Bauer, Springer, or trading for Lindor. The Mets could still have a solid offseason. The Trevor May signing was great. Lets say they add McCann, then make free agent deals for Manuel Margot, Justin Turner, Corey Kluber, Jon Lester, and Brad Hand. That is not a bad offseason. In fact, some could say that it was a very successful one. But not for the Mets in their first offseason after Steve Cohen bought the team.