Alex Cobb ended up at nearby St. Anthony's Hospital after Saturday's 8-0 loss to the A's after complaining of discomfort in his right hand.
The Rays didn't provide further details other than Cobb was being examined by team orthopedic surgeon Koco Eaton.
"I have no idea," manager Joe Maddon said when asked if he could shed more light on the topic. "He did not complain of anything during the course of the game. I was advised of the problem during the game."
Cobb's discomfort might explain his poor outing and why the A's stole seven bases — the most ever in one game against the Rays.
Five of those steals came with Cobb on the mound, and while he did a poor job of holding runners on base, it could be because he was distracted with the issue with his right hand.
The loss snapped the Rays' three-game winning streak and dropped them to 10 games back in the wild-card standings.
A's right-hander Brandon McCarthy held the Rays to five hits in eight innings and provided a match-up Maddon said he just didn't like against his hitters.
That might have been one reason why the bounce the Rays had after winning three straight was missing against a pitcher who evened his record at .500 with the win.
The fact the Rays fell behind early might have been another reason, since they are 43-13 this season when they score first.
Cobb, so solid for so much of his rookie season, allowed a career-high five runs in 41/3 innings.
The outing innings matched the shortest of his career and snapped a string of four straight quality starts.
Rookie catcher Robinson Chirinos, who had two more hits to raise his average to .300, had trouble controlling the running game as the A's stole seven bases.
Chirinos is 2-for-25 when it comes to throwing out base stealers.
The blame doesn't rest entirely with Chirinos.
"The pitchers did not do a very good job," Maddon said. "We were kind of slow to the plate and we did not do a good job of holding runners."
The A's certainly detected that flaw and turned the game into a track meet, with center fielder Coco Crisp stealing a career-high four bags, which was one shy of the club record shared by Bert Campaneris and Rickey Henderson.
It was like the Green Bay Packers' famed Power Sweep of the Vince Lombardi Era that Maddon fondly recalls when talking about doing something to perfection so the other team can't stop it even when they know it's coming.
The Rays knew the A's were running and couldn't do anything about it.
"(Chirinos) had a shot at (Scott Sizemore) had he made a better throw, otherwise he didn't have much of a chance," Maddon said.
The A's scored two runs in the third inning, the first on the first of two home runs by right fielder David DeJesus. The second came home when Adam Rosales bounced out to shortstop with Sizemore on third.
Crisp reached on a bunt single in the third inning, stole second, moved to third on a ground out by Hideki Matsui and scored on a sacrifice fly.
Sizemore singled in the fourth and stole second, sliding in ahead of the throw Maddon eluded to that short-hopped its way past Ben Zobrist. Sizemore eventually scored on a single by Jemile Weeks.
Crisp singled and stole second and third in the fifth. He came home on a sacrifice fly by Cliff Pennington.
After the game, A's manager Bob Melvin said Crisp is questionable for this afternoon's game with a strained right calf.
Maddon pulled Cobb with the bases loaded and one out in the fifth inning.
Brandon Gomes came in and allowed the sac fly to Pennington, the first of five batters Gomes faced and retired.
The game drew a crowd of 24,939 to Tropicana Field, most of which stayed around for the Goo Goo Dolls concert.
It was just the sixth time the Rays have lost on a concert night, and the loss prevented them from winning their third straight series, something they haven't done since late June.