ANAHEIM -- A constant gripe among Rays fans is the fact B.J. Upton plays such a shallow center field.

According to Davey Martinez, the former Major League outfielder and current Rays bench coach, Upton plays the shallowest center field in baseball, and for a good reason: He can.

"As a hitter, you see somebody standing that shallow, it's frustrating knowing he can go back and get the balls like he does," Martinez said. "I mean, every now and then you're going to get burned. But for the most part, just think about all the hits he's caught. Because, literally, if you're playing back, those are hits. There have been at least two dozen balls I think other center fielders never would have gotten to that B.J. has."

Upton moved to center field in 2007, and he said it took him about a year to gain enough courage to play as shallow as he does.

"When I first started, I told them I was going to play a little deeper until I got comfortable, and I think last year I really started working on it in Spring Training," Upton said. "Throughout the year, I was fine and got more and more comfortable."

Though Martinez clearly is in Upton's corner, he understands the perspective a lot of fans have.

"Definitely, because they see a ball go up -- right away they think it should be caught," Martinez said. "Some of the balls, even if he was playing back, he might not be able to catch them anyway. A lot of those balls that we tend to notice that he doesn't catch are usually balls to the gap that he's playing a guy a certain way and a guy hits the ball the other way. You're just not going to catch those balls."

Martinez went on to say that Upton's position disturbs opposing teams.

"I hear all the time from opposing hitters, 'When are you guys going to move B.J. back?'" Martinez said. "So that's great to know. We tell him all the time, you're doing us more good playing in than playing deep. More balls are going to get hit shallow than deep. And if the ball's hit high enough, he has no problem."

Upton said he has adjusted some to certain hitters, though.

"If you've got a guy at the plate who can hit it out of the ballpark, you've got to give yourself a little more room," Upton said. "So that's something I've kind of added in. But the guys who can put you in the seats, you give them a few more steps back."