OAKLAND, Calif. -- The Oakland A's scored a season-high tying seven runs in the seventh inning and rallied for an 8-2 victory against Tampa Bay, but their win Sunday came at a cost.

Right-hander Kendall Graveman strained his left oblique on his second to last pitch in the sixth inning and will be examined by doctors Monday morning.

"Might be a little while," A's manager Bob Melvin said. "He was pitching well. He was going to go back out for the seventh. His pitch count was under control, but we may be looking at an issue with him."

Graveman pitched six shutout innings, and first baseman Mark Canha went 2-for-4 with four RBIs and a three-run triple in the seventh inning.

After dropping the first two games in the series, the A's won the finale and prevented Tampa Bay from its first sweep of the A's at the Coliseum.

Graveman allowed just three hits while striking out three and walking one. He left the game with a 1-0 lead after throwing 84 pitches and got a no-decision.

"Just one of those things," Graveman said of the injury. "Never felt it before, but that's kind of what happened. Precautionary. See how it feels tomorrow and go get it checked out and see what's up."

Graveman had gone 0-5 with a 6.89 ERA over his previous seven starts, but he threw his second straight strong game this season against Tampa Bay. In a 5-0 A's victory on May 23 at Tropicana Field, he blanked the Rays on three hits over six innings, striking out six and walking two in his first career start against Tampa Bay.

Rays right-hander Jake Odorizzi gave up two runs and three hits over six innings and got a no-decision. He struck out four, walked one and left the game with a 2-1 lead, a runner on first and no outs in the seventh after walking third baseman Danny Valencia.

After Odorizzi exited, the A's went on to score seven runs in the inning, hammering the Rays' bullpen and taking an 8-2 lead.

"Just good at-bats the whole inning, from everybody," Canha said. "Guys were just really dialing in. I wasn't surprised when we busted it open like that."

The A's sent 12 batters to the plate and had eight hits in the inning, including Canha's bases-loaded triple and a two-run single by second baseman Eric Sogard. Catcher Steven Vogt had two hits in the inning, including a double.

Valencia had an RBI single to go with his walk, and designated hitter Billy Butler doubled. Second baseman Brett Lawrie had an RBI single in two at-bats, and center fielder Billy Burns singled.

"That was fun," Vogt said. "We haven't really had offensive fun like that in a while."

Rays right-hander Steve Geltz (2-5) gave up four runs on four hits over one-third of an inning. Right-hander Matt Andriese gave up two runs on four hits in two-thirds of an inning.

"Everything I threw was getting hit," Geltz said. "I wasn't making good enough pitches."

The Rays' bullpen blew a lead in the seventh inning or later for the fourth time on their 10-game road trip, finishing 4-6.

"We've given up some leads, and when you do, the pen becomes the focal point," Rays manager Kevin Cash said. "We have a lot of confidence in the guys coming out of the bullpen."

Odorizzi had a perfect game through three innings, but Burns drilled a leadoff triple to right-center field in the fourth, and Canha grounded an RBI single to right, giving the A's a 1-0 lead.

The Rays rallied for two runs in the seventh, taking a 2-1 lead. A's left-hander Sean Doolittle made his second relief appearance of the season and first since being activated from the disabled list Saturday. He gave up two runs on two hits and walked two in two-thirds of an inning.

"Overall, mechanically, and the way the ball was coming out I was happy with how I felt," Doolittle said. "The adrenaline was going really fast. It didn't matter how much I tried to slow myself down, I was just going a little bit too fast."

Doolittle threw 23 pitches and topped out at 93 mph.

Right-hander Fernando Rodriguez (3-1) pitched 1 1/3 innings, blanking the Rays on two hits for the win.

NOTES: Oakland 3B Danny Valencia, who missed Saturday's game with a sore lower right hamstring, returned to the lineup Sunday. An MRI revealed that Valencia has tendinitis, A's manager Bob Melvin said. ... Rays LF Desmond Jennings was out of the starting lineup for just the second time since coming off the 60-day disabled list Aug. 14. He hit .344 in eight starts since returning from left knee surgery. He entered Sunday's game as a pinch hitter and had a sacrifice fly. ... Rays DH/LF John Jaso started in left field for the fifth time in his career, all this season. He has spent most of his career as a catcher. Jaso, a former Athletic, hit cleanup for the first time this year.