With baseball's all-time saves leader done for the season and possibly his career, the New York Yankees must now find a way to save their championship window of opportunity from potentially closing.
Rivera, who has amassed 608 saves in becoming the majors' leader in that category as part of what will undoubtedly be a Hall of Fame career, tore the ACL in his right knee shagging fly balls in the outfield prior to Thursday's series opener between the teams. The 42-year-old reliever had considered making this his final season, and will maintain that timetable as he prepares for surgery and rehabilitation.
"At this point, I don't know," Rivera said somberly. "Going to have to face this first. It all depends on how the rehab is going to happen, and from there, we'll see."
It will be the first time since 2003 the extremely durable Rivera will be on the disabled list, and he had converted his last five save attempts and strung together eight consecutive scoreless appearances after a loss on opening day.
"Mo is a vital part of this team on the field, off the field. He's going to be missed," said Derek Jeter, who came up with Rivera in 1995 and won five World Series titles together, to the team's official website. "There's no other way to put it. You don't replace him. Someone else can do his job, but you can't really replace him."
That "someone else" for New York (13-12) could be David Robertson - unscored upon in 11 innings over 11 appearances this season while striking out 18 - or Rafael Soriano, who had 45 saves for Tampa Bay in 2010 before signing with the Yankees prior to last season. Soriano has given up two runs in nine innings in nine games thus far.
After watching Rivera leave the field on a cart, the Yankees (13-12) fell behind by three runs, and their comeback came up short in a 4-3 defeat. Mark Teixeira, who had two RBIs, hit into a double play after the first two hitters in the ninth inning reached base and Rodriguez grounded out to end the game with Derek Jeter on third.
The win was the first in 11 home games for Kansas City (8-16), and Mike Moustakas led the way with a home run and a career high-tying three RBIs.
"It's a load off," manager Ned Yost said. ''We don't have to talk about not winning games at home anymore. That's a good thing. Hearing the fans in the ninth inning was like music to my ears."
CC Sabathia (3-0, 4.58 ERA) hopes to help the Yankees regroup by winning in a fourth consecutive start. The left-hander yielded a season-low two runs and four hits over eight innings during a 6-2 win against Detroit on Sunday.
"We've seen him get increasingly better every time he's gone out, and that's encouraging to us," manager Joe Girardi told the team's website.
Sabathia has 17 wins in 34 starts against the Royals, his second-most victories over one opponent in his career, and he has claimed one in each of the last three matchups, including two at Kauffman. He's 10-5 with a 3.81 ERA over 18 career outings in Kansas City, where he's won four of his last five starts.
While Sabathia will try to further one of the best career starts, the Royals' Bruce Chen (0-3, 4.23) will attempt to avoid dropping a fourth consecutive start.
The left-hander has been given a combined five runs of support in his five outings this season but didn't help himself in a 7-4 loss in Minnesota on Sunday, giving up a season-high six runs over 2 2-3 innings.
Chen is 2-5 with a 6.06 ERA in 13 career starts against the Yankees but earned a win in his most recent matchup Aug. 17 in Kansas City, allowing three runs over six innings.
Jeter, hitting .404 this season, has gotten more hits off Chen than any other batter, going 16 for 38.