Shortstop Corey Seager was left off the Los Angeles Dodgers' roster for the NL Championship Series against the Chicago Cubs on Saturday.
The Dodgers announced Seager's surprise omission due to an apparent back injury several hours before Game 1 at Dodger Stadium.
Los Angeles also dropped reliever Pedro Baez from its roster. Infielder Charlie Culberson and outfielder Joc Pederson were added.
Chicago made only one change from the last playoff round, adding right-handed reliever Hector Rondon and removing left-handed reliever Justin Wilson.
Seager complained of back soreness during the Dodgers' NL Division Series clincher in Arizona on Monday, and 2016 NL Rookie of the Year didn't participate in team workouts this week. Manager Dave Roberts said he was very optimistic on Friday that Seager would play in the NLCS.
Instead, the All-Star shortstop can't play again this season unless the Dodgers reach their first World Series since 1988.
Seager led the Dodgers with 159 hits this season, batting .295 with 22 homers and 77 RBIs while playing in 145 games. He went 3 for 11 with four walks and two RBIs in the division series, batting second in the Los Angeles lineup in all three games.
Kike Hernandez, Chris Taylor and Culberson all worked out at shortstop Friday for the Dodgers. The versatile Taylor was the Dodgers' center fielder during the NLDS, but he made 96 appearances in the outfield this season and 44 in the infield, including 14 games at shortstop.
Pederson is batting .071 with no homers since July, but the Dodgers could need him in center field if Taylor plays shortstop.
Baez didn't pitch in the NLDS against Arizona.
Culberson famously homered to clinch the Dodgers' NL West title in announcer Vin Scully's final home game last season, but the infielder spent most of this season at Triple-A, appearing in only 15 games for the Dodgers.
Rondon was the Cubs' closer in 2014 and 2015, but moved to a setup role last season after Aroldis Chapman's arrival. He appeared in 61 regular-season games this year, going 4-1 with a 4.24 ERA in an up-and-down campaign.
Chicago acquired Wilson in a trade with Detroit on July 31, adding a veteran lefty who had 13 saves for the Tigers this season. The Southern California native wasn't great in his two months with the Cubs, posting a 5.09 ERA with 19 walks in 23 appearances.
Manager Joe Maddon chose Wilson for the NLDS over Rondon, only to switch it up against the Dodgers. Chicago has two left-handed relievers on its roster with the removal of Wilson, who pitched once in the division series against Washington, getting two outs in Game 4.