It'll be the first playoff action that Kansas City fans have seen in a generation, as the Royals secured their first playoff berth since 1985. They wrapped up that guarantee a few days before Oakland, which needed a win on Sunday afternoon against the Rangers to capture a bid.
And while it was a banner season for the Royals -- who finished the season a game back of the Tigers in the AL Central -- the A's couldn't prevent a disappointing fade through much of the regular season's second half. In control of the AL West with a six-game lead as late as June 21, Oakland fell to as many as 12 games behind the Angels at the end of September.
Still, the A's are postseason bound for the third straight year and looking to fare better against Kansas City than they did in the regular season. Over the course of seven meetings this year, the Royals won five games (though the A's outscored K.C. by two runs).
But this is the postseason, when anything can happen. Here's a look at how these teams stack up, position by position.
This matchup pits an All-Star in Salvador Perez against an Oakland latecomer in veteran Geovany Soto. Derek Norris has had a breakout year (.270 average, 55 RBIs, 10 homers) in his third full season and first behind the plate for more than 100 games, but Soto -- purchased on Aug. 24 from the Rangers -- has been getting a fair share of looks this month and is expected to play Tuesday. Perez experienced a slight dip in production since the All-Star break, but he still gets the nod as the better defensive catcher, with eight defensive runs saved to Soto's zero (and Norris' -3). Advantage: Royals
Kansas City's Eric Hosmer was hitting just .246 at the end of June when he went on a 24-for-56 stretch (.429) in 14 July games to turn things around. But when he was hit on the right hand by a pitch at Boston, it turned the Royals' lineup upside down. The Gold Glove Award winner is a difference-maker in the lineup and at first base -- much more so than Oakland's Stephen Vogt, who will get the platoon start against the right-hander James Shields. Vogt's splits against righties (.291 average vs. .205 against lefties) are favorable, but he's hit just 5-for-23 (.217) against Kansas City this year. Advantage: Royals
||KC 9, OAK 8
Omar Infante came to Kansas City this year as a do-everything utility man after the Royals had seen a revolving door of players at second for years. He had been a tough out with Detroit -- especially in 2013, when he hit .375 against Kansas City -- and they'll certainly hope his 30 games of postseason experience come in handy. For Oakland, it'll be former Royals infielder Alberto Callaspo, who is 2-for-5 against Shields and 5-for-24 against the Royals this season. Advantage: Royals
After a breakout campaign in 2013, Josh Donaldson just about replicated all of his numbers (29 homers and 98 RBIs are up from his totals last year) except average (down from .301 to .255 this season). Still, he's the heart and soul of the Oakland lineup and the A's will need him to be far more productive than he was in last year's playoffs (3-for-21 with zero RBIs and eight strikeouts). Like many of his homegrown Royals teammates, Mike Moustakas has never seen the playoffs. And his numbers against the A's this year -- 2-for-22, including 0-for-5 against A's starter Jon Lester -- are bleak. Advantage: A's
Possessing one of the best arms in the game at his position, Alcides Escobar has been sturdy at shortstop for the Royals since he was acquired from Milwaukee in the Zack Greinke deal four years ago. He's also an extraordinarily efficient base stealer (he's stolen 88 bases and been thrown out just 11 times since 2012). Oakland counters with Jed Lowrie, whose offensive numbers are similar (with the exception of baserunning). Escobar is 2-for-7 this year against Lester and Lowrie is 1-for-3 against Shields. Lowrie's 17 games of postseason experience (.176 average with Boston and Oakland) give him an ever-so-slight edge. Advantage: A's
After looking as if 2014 would be the most disappointing season in recent memory for Billy Butler, the veteran slugger turned it on in September. He has a hit in eight of his last 10 games and multiple hits in five of them to bring his average for the year up to .271. But Oakland's Adam Dunn may have an extra bit of motivation as the veteran slugger gets his first crack at the playoffs after 14 years in the big leagues. Dunn is a career .200 hitter (with 16 strikeouts and one homer in 35 career at-bats) against Shields, while Butler is hitless against Lester in nine at-bats this year. Advantage: A's
With an impressive all-around game, Alex Gordon has worked his way into the AL MVP conversation this year. According to FanGraphs, Gordon has saved 27 runs in left field while recording eight assists. He's hit .266 with 19 homers and 74 RBIs this year, with an impressive .336 average with runners in scoring position. And like Gordon, Oakland's Brandon Moss (likely to platoon in favor of Jonny Gomes against Shields) is an essential key in his team's lineup with all-around game at the plate (.234 average, 25 homers and 81 RBIs). But Gordon's defense gives him the slight edge in a matchup that could very well be a push. Advantage: Royals
The kind of team speed the Royals have is an asset on the basepaths and in the field. That's the case for Kansas City center fielders Lorenzo Cain and Jarrod Dyson, who excel at taking away hits from opponents and at getting under opponents' skin on the bases when they get on base. Between the two of them, the Royals led the AL in defensive runs saved in center (the A's were 12th, according to FanGraphs) and were first in the Majors in Ultimate Zone Rating (the A's were 20th). Cain stole 28 bases and Dyson swiped 36, while Oakland's Coco Crisp took just 19. Speed kills in the playoffs. Advantage: Royals
Josh Reddick is heating up at the right time for the A's, and they'll need production from him without Yoenis Cespedes, who fueled Oakland's offense in the playoffs last year. Over 19 September games, Reddick hit .313 with two homers and 13 RBIs. But the Royals have a hot right fielder of their own in Nori Aoki (.369 average with six doubles, two triples and 10 RBIs in 23 September games). Reddick's power and splits against Shields (4-for-6 with two homers this year) give him the slight edge. Advantage: A's
With a team as defensively gifted as the Royals, there aren't likely to be many late-innings changes for defense, so their bench players are most useful on the basepaths. Cain or Dyson (whichever is the odd man out in center field) is dangerous on the basepaths and youngster Terrance Gore is one of the fastest players in the Majors. Beyond that, it's veteran Raul Ibanez (44 career playoff games) and Josh Willingham. Oakland receives more well-rounded production from Vogt, Sam Fuld, Soto and Eric Sogard. In a series, the advantage would go to Oakland. But in one game (in the AL, with no need for pinch-hitters), it's those pinch-runners who could mean everything. Advantage: Royals
For the purpose of this one game, it's a matchup between Shields and Lester. Shields has earned the nickname "Big Game James" for his performance in pressure situations such as Tuesday's game, while Lester is no stranger to the playoff spotlight after spending the first nine years of his career with the Red Sox (6-4 career postseason record and 2.11 ERA). He was unflappable during Boston's World Series run last year, going 4-1 with a 1.56 ERA. All of Shields' postseason starts have also come with a different club -- the Rays -- but his 2-4 record and 4.98 ERA don't quite stack up against Lester's postseason resume. Advantage: A's
When people think of strong bullpens around baseball, they immediately think of Kansas City and its ever-formidable late-innings staff. The eighth- and ninth-inning duo of Wade Davis (9-2 record, 1.00 ERA, 109 strikeouts in 72 innings) and Greg Holland (1.44 ERA, 46 saves in 48 opportunities, 90 strikeouts in 62 1/3 innings) may be the best in baseball, and seventh-inning man Kelvin Herrera is no slouch himself. But Oakland, statistically, may have the best 'pen in the league. The A's bullpen was second in the league in ERA (2.59), first in walks allowed (122), second in opponents' batting average (.222), first in on-base percentage (.279) and OPS (.609) and total bases allowed (565). But considering neither team is likely to throw more than three or four relievers in this one game, the slight edge has to go to the team with the most elite relievers. Advantage: Royals
Bullpens are often measured by their closers, and these two teams each have excellent ones. Sean Doolittle (2.73 ERA, 22 saves in 26 opportunities, 61 appearances) has been dependable in Oakland, but he simply has not been as lights-out as the dominant Holland. The Royals closer's WAR (2.5) is nearly twice that of Doolittle (1.3) and his 46 saves lead all playoff closers. Advantage: Royals