3. Tom Seaver - 1971
In my opinion, the best season of Tom Seaver's career came in 1971. Despite pitching on a fourth place team, Seaver did everything he could to try and will the Mets back to the postseason.
In Seaver's 35 starts, he went 20-10 with a league leading 1.76 ERA. He'd throw 286.1 innings and strike out a league leading 289 batters. The 9.1 K/9 led the league and was Seaver's career best mark. He'd walk just 1.9/9 and allow just 0.6 HR/9.
Seaver would go at least nine innings 21 times, going more than nine innings twice. He'd throw four shutouts and was dominant all season long.
Seaver had many starts that stuck out. He had a complete game shutout against the Pirates in a 1-0 win which saw him strike out 14 batters, allow just three hits, and not walk a batter. There was a ten inning masterpiece in San Diego which saw him strike out 14 batters and not allow a run. The Mets would lose this game 1-0.
Somehow, someway, Fergie Jenkins stole that Cy Young Award from Seaver. Jenkins went 24-13 with a 2.77 ERA in his 39 starts, striking out 263 batters. Jenkins' ERA was over a run higher, and struck out 26 fewer batters than Seaver despite making four more starts and throwing 38.2 more innings.
There's the Wright MVP that was stolen from him by Jimmy Rollins, and there's this outrageous result as well. Regardless, Seaver was unhittable all year and deserves a ton of praise for everything he did in the 1971 season.