Bryce Harper and the Phillies will head home to face the Miami Marlins in a best-of-three National League wild-card series starting Tuesday.
Showalter ended his pregame news conference by saying the Mets ---- told him they were "going to go in a different direction with the manager next year."
Showalter's exit after two seasons -- the shortest of his five big league stints -- clears the way for Stearns to pick the next manager.
"I wish things could have gone better this season because the Mets fans deserve that," Showalter said as he appeared to fight back tears. "In my heart, I always wonder what could have happened if this happened or that happened, but I try not to live in that world.
"It's not the ending I wanted, but I still love this city and the players."
The Mets stood in front of the dugout and joined the crowd of 41,212 in giving Showalter a standing ovation as he exchanged lineup cards before first pitch. A message reading "Thank You Buck" was displayed on the scoreboard.
Showalter received another warm ovation as he headed back to the dugout following a pitching change in the ninth inning.
Showalter led the Mets to a 101-61 record last season, when he was voted NL Manager of the Year. New York lost to San Diego in a wild-card series, then added three-time Cy Young Award winner Justin Verlander to its pitching staff during the offseason.
The Mets boosted their payroll to a record $355 million on opening day, but wound up dealing Verlander, Max Scherzer and several other veterans ahead of the Aug. 1 trade deadline.
The Mets fell to 74-87 on Sunday -- the largest season-to-season drop-off in the majors this year.
Showalter is 1,726-1,665 (.509) in 22 seasons as a big league manager with the Yankees, Diamondbacks, Rangers, Orioles and Mets - guiding all those organizations to the playoffs besides Texas.
Brandon Marsh homered and finished with four RBIs for the Phillies (90-72), who won four more games than a season ago, when they qualified as the final wild card in the NL before reaching the World Series. Bryson Stott, Johan Rojas and Garrett Stubbs each had RBI hits, and Bohm also had a sacrifice fly.
Matt Strahm tossed a perfect first inning as an opener before Nick Nelson (1-0) won his season debut with 5 1/3 innings of one-run ball.
José Butto (1-4) gave up two runs and struck out four in six innings.
Tim Locastro homered in the third - the first of just two hits for the Mets.
The Mets held a moment of silence before the game in honor of Tim Wakefield,.
The Mets drew 41,212 for Sunday's finale and welcomed 2,573,555 fans this season, a slight increase over last year's 2,564,737.
Phillies: SS Trea Turner (left elbow bruise) felt fine but sat out the meaningless regular-season finale. Manager Rob Thomson said Turner would have played in a game with significant implications.
Phillies: RHP Zack Wheeler (13-6, 3.61 ERA) will start the wild-card series opener Tuesday in Philadelphia against Miami.
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