CHICAGO (AP) Most of Kyle Schwarber's major league firsts are long past, tucked away for safe keeping, or displayed on a shelf somewhere. His No. 12 Cubs jersey hangs in stores all over Chicago.
The rookie slugger, who plays with a calm that belies his experience, takes it all in stride. But even Schwarber is looking forward to his postseason debut.
''I got an idea of kind of what it will be like,'' he said, ''but then it's probably going to be nothing close about what it's going to be like.''
Schwarber gets to find out next week when the Cubs make their first playoff appearance since he was a teenager growing up in Middletown in southwestern Ohio. Schwarber and teammates Kris Bryant, Addison Russell, Jorge Soler and Javier Baez are among a stellar group of big league rookies who could determine which teams play deep into October.
''I'm going to really count on kind of the veterans who've all been there and kind of give us the low down on what it's going to be like and how to prepare,'' said Schwarber, who had two hits and walked twice in a 4-1 victory at Cincinnati on Tuesday night. ''They say it's a different feeling every time, so I'm looking forward to it personally. I want to get that feeling.''
Schwarber had 16 of the 653 homers for rookies heading into Tuesday's games, the highest such total for a single season in major league history, according to STATS. The 5,727 hits and 9,164 total bases for rookies in 2015 also rank among baseball's best classes, same for the 409 wins and 6,692 strikeouts.
Bryant, the front-runner for NL Rookie of the Year, powered Chicago to a spot in the Oct. 7 wild-card game, but several other rookies also had prominent roles on contending clubs.
Noah Syndergaard and Steven Matz likely will be a part of the Mets' postseason rotation. Michael Conforto is batting .280 with eight homers and 24 RBIs in 52 games since he made his major league debut on July 24.
New York's young arms played a key role in the Mets' overtaking Washington for the NL East title in the second half of the year.
''I think once you've made enough starts up here where you realize you can compete, I think you throw the rookie stuff away,'' manager Terry Collins said. ''There's no reason to think you can't win big games just because you don't have the years in, when you've gone out and competed against good teams and good lineups and gotten them out. I think that stuff is pretty much along the wayside.''
Across town in the Bronx, Greg Bird has 10 homers and 29 RBIs in just 41 games for the Yankees, helping make up for the loss of first baseman Mark Teixeira to a right leg injury. Right-hander Luis Severino might be New York's most reliable starter as it tries to secure a playoff spot, going 5-3 with a 2.77 ERA in his first 10 major league starts.
Bird, who turns 23 in November, showed off his young age when he pointed to a - gasp - wild-card team when asked for his favorite playoff memory growing up.
''The Rockies in 2007, that was intense, because we were in Denver then, I was in high school,'' he said. ''That was a cool postseason run. I just watched on TV.''
Eight years after then-rookie Troy Tulowitzki helped Colorado to its only World Series appearance, another generation of shortstops are hoping to have a similar effect this year.
Russell and Corey Seager of the Los Angeles Dodgers are already into the postseason. Houston star Carlos Correa and Cleveland's Francisco Lindor, the top contenders for AL Rookie of the Year, are trying to grab a spot in the final days.
Seager was promoted from Triple-A Oklahoma City on Sept. 3 and is batting .333 in 23 games with the NL West champions.
''We've got some guys handling it pretty well, and there's some other teams, you talk about like a Correa or somebody like that have been huge,'' Dodgers manager Don Mattingly said. ''Obviously, there's some young guys having good years.''
Seager got an opportunity to be an everyday player when Jimmy Rollins was hampered by a finger injury. Schwarber made the most of a similar opening when veteran catcher Miguel Montero sprained his left thumb in July.
Schwarber batted .348 with five homers and 15 RBIs in his first 21 games after the All-Star break, including a memorable night near his hometown when he connected twice and drove in four runs in a 5-4 victory against the Reds.
He played in some big games down the stretch as Chicago secured its first playoff berth since 2008, and he is hoping that experience will pay off in the postseason.
''You got to know that it's the major leagues, every possible situation is probably going to happen,'' he said, ''and you've just got to stay level and keep your head in the same spot through it all.''
AP Sports Writers Joe Kay in Cincinnati, Janie McCauley in San Francisco and Ron Blum in New York contributed to this report.
Jay Cohen can be reached at http://www.twitter.com/jcohenap