Grilli, appearing in his second game for the Angels, came on in the bottom of the ninth with the score tied at 4-4. Grilli struck out Billy Butler, but then grazed Alex Gordon with a pitch, putting a runner on first. The inning appeared over when Salvador Perez hit a grounder right at the shortstop, but Howie Kendrick botched the catch, allowing Gordon advance to third and Perez to reach base safely.
The error set the stage for Infante, who connected on the first offering he saw from Grilli:
The Angels struck for two runs in the top half of the first. Kole Calhoun led off the game with a solo shot, jumping over a Jeremy Guthrie fastball that stayed up and caught far too much of the plate. Mike Trout followed with a single, but Guthrie retired the next two hitters and should have escaped the inning with only one run allowed. Unfortunately, Lorenzo Cain misjudged an Erick Aybar flyball, allowing Trout to score.
The Royals allowed another unearned run to score in the top of the third. Calhoun hit a groundball to Eric Hosmer, but the first baseman made a poor throw to Guthrie, allowing Calhoun to reach base safely. Trout then drew a walk, but Guthrie forced Albert Pujols to ground into a double play; the umpire originally ruled that Trout was safe at second base on the play, but replay showed that Infante made a great grab and kept his foot on the bag. The overturned call proved key, as Josh Hamilton followed with a double that plated Calhoun and would have scored Trout had the call not been corrected.
Kansas City had runners reach base against C.J. Wilson in the first three innings, but didn't break through until the fourth. Wilson started the inning by hitting Perez, then surrendered an Infante double. Danny Valencia drove in Perez with a single, followed by an Alcides Escobar walk to load the bases with none out, one run already scored in the inning. Jarrod Dyson went down swinging for the first out of the inning, but Cain smacked a double to left, scoring Infate and Valencia to tie the game.
Hosmer followed Cain with a lineout to short, then Mike Scioscia ordered Wilson to give Butler a free pass, loading the bases for Alex Gordon. Wilson ended up walking Gordon as well, forcing home Escobar to give the Royals a 4-3 lead. Wilson was yanked for the game after the Gordon walk, and Cory Rasmus recorded the final out of the inning.
The Royals had some opportunities against Rasmus in the next couple of innings, but Escobar getting picked off second base squandered one opportunity, plus Hosmer, Butler and Gordon all struck out against Rasmus in the sixth after Cain led off the inning with a double. Kevin Jepsen worked two innings of relief after Rasmus, and the KC offense managed even less against the set-up man.
Los Angeles tied the game at 4-4 thanks to an Erik Aybar solo homer in the sixth. The Angels also loaded the bases against Guthrie in the bottom of the seventh inning with two outs, but Kelvin Herrera helped the Royals escape the jam by inducing a Pujols flyout to center. Wade Davis and Greg Holland each worked a fairly uneventful inning of relief to keep the game knotted into the bottom of the ninth, setting up the Infante walkoff.
Cain finished the day 4-5 at the plate, including three doubles. Infante went 3-4 on the day, while Escobar and Valencia both had multi-hit games.
The Royals sit at 42-39 on the season, 3 1/2 games back of the Detroit Tigers in the AL Central. The team will travel to Target Field on Monday to start a three-game series against the Minnesota Twins; Danny Duffy will face Yohan Pino in the opener.