With one out and Baltimore ahead 2-0, Simon (0-1) allowed a single by Asdrubal Cabrera and walked Mark Grudzielanek.
Shin-Soo Choo followed with an RBI single before Kearns slammed an 0-2 changeup to left for his third homer.
Mike Redmond added a two-run double off Cla Meredith before Trevor Crowe, just called up from the minors, capped the Indians' biggest inning of the year with a two-run homer.
Mitch Talbot (5-2) worked eight innings, allowing two runs and five hits. He walked two and struck out three.
Ty Wigginton homered twice for Baltimore.
At Kansas City, Jake Peavy settled down after a rocky first inning and pitched into the ninth to win his third straight start.
After the start was delayed 61 minutes by rain, Peavy (3-2) gave up a three-run double to Alberto Callaspo in the first inning and Billy Butler's homer in the third. But the right-hander allowed only three singles after that before he was pulled with one out in the ninth.
Royals starter Luke Hochevar (3-2), who threw 26 pitches in the seventh while retiring only one, gave up five runs on seven hits and two walks in 6 1-3 innings.
At Toronto, Ricky Romero struck out 12 in his first career shutout and Jose Bautista hit two home runs.
Romero (4-1) allowed just five singles and walked one. The left-hander lowered his ERA to 2.88 and matched his career best for strikeouts while extending his unbeaten streak to five starts.
It was Bautista's second multihomer game of the season and fourth of his career. He went 3 for 4 with five RBIs.
Bautista led off the fifth with his eight homer, a drive to left on an 0-1 pitch from Scott Feldman (1-4). He hit a two-out RBI single in the sixth and a three-run drive off Darren O'Day in the eighth.
Feldman, who is winless in his last six starts, allowed five runs and nine hits in 7 1-3 innings.
At St. Petersburg, Florida, Willy Aybar homered leading off the bottom of the ninth inning, giving baseball-best Tampa Bay the victory.
The Rays wiped out a 2-0 deficit in the eighth inning, then won it with Aybar's drive to right-center on a 3-2 pitch from Jesus Colome (0-1).
Rafael Soriano (2-0) pitched a scoreless ninth in relief of James Shields to get the win.
The victory enabled the Rays to avoid falling level with the New York Yankees for the best record in the majors. At 25-11, the AL East leaders are off to the best start in franchise history.
Jason Vargas allowed two runs and four hits in seven-plus innings for Seattle. Mike Sweeney homered for the third straight game and Ichiro Suzuki had two more hits to match a career best with seven consecutive multihit games.
At New York, Andy Pettitte put to rest any concern about his left elbow, holding the Twins to two hits into the seventh inning.
Mark Teixeira and Jorge Posada hit long two-run homers in the seventh after stingy Francisco Liriano was done.
Pettitte (5-0) pitched 6 1-3 scoreless innings in his first outing in 10 days, winning his fifth consecutive decision to match his career-best start in 1997. He left his previous game May 5 with elbow inflammation and was forced to skip a start as a precaution.
Liriano (4-2) allowed three runs and nine hits in six innings for Minnesota. He struck out seven and walked none.
At Anaheim, Kendry Morales drove in five runs with a pair of homers, including a go-ahead shot off emergency starter Tyson Ross, as the Los Angeles Angels reached double digits in runs for the first time this season.
Ervin Santana (2-3) earned his first win since April 18, allowing three runs — two earned — and seven hits over six innings with six strikeouts and three walks. The right-hander is 11-2 with a 1.50 ERA in 18 career appearances against the A's, including 16 starts.
Torii Hunter hit a run-scoring double during a four-run seventh against Chad Gaudin for his 900th career RBI, and Morales followed with his ninth homer to make it 11-3.
