Frank Thomas wants baseball to start testing for steroids, saying he feels “cheated” if other players are using drugs.

“I don’t know who’s on and who’s not on,” the two-time MVP said Wednesday before the Chicago White Sox played the New York Yankees. “There is definitely more activity in the weight room nowadays. I was hoping that it was just old guys working hard in the weight room.

“I really think it’s time for testing. It really is.”

Two high-profile former players said recently that steroid use is rampant in the major leagues. Ken Caminiti estimated that at least half of major leaguers use steroids, and he told Sports Illustrated he was on them when he won the NL MVP award in 1996.

Jose Canseco put the number even higher, at 85 percent.

New York Mets manager Bobby Valentine thought those estimates were overblown.

“Only if it’s in the water or there’s some way players are ingesting them without knowing it,” Valentine said before his team’s home game against Philadelphia. “I think it’s a total exaggeration unless you’re saying some of the stuff like MetRx mix and the blender stuff is a steroid, then I stand corrected.

“As far as something injected or prescribed, I think it’s preposterous to say 85 percent.”

Caminiti said steroid use was common knowledge in clubhouses, but players and managers disputed that.

“I haven’t seen anybody use, or anything like that,” Thomas said. “I don’t think guys talk about it. I think the guys that are doing are keeping it quiet.”

There may be rumors about certain players, but Yankees manager Joe Torre said that’s all he’s ever heard rumors.

“I’m not sure how widespread this problem is,” Torre said. “I’ve seen players go from tall, skinny guys to tall, strong guys. Sure, you can say he’s got to be doing something, but I’ve never had anybody tell me for sure that, ‘This person is doing this.’ It’s always, ‘I heard this guy is doing it.”‘

Toronto manager Buck Martinez believes his clubhouse is clean.

“I would fight for the character of my 25 players,” he said. “There are so many wonderful people that play baseball. You have to be careful not to paint everybody with the same brush.”

But as a player, Martinez admitted he didn’t always know what others were doing around him when baseball went through a drug-using scandal in the 1980s.

“I was naive to that when my teammates were involved,” Martinez said before the Blue Jays played Boston.

While the NFL and NBA prohibit steroids and test for them, the NHL and major league baseball have no policy regarding their use. A ban in baseball, or even testing players on 40-man rosters would have to be collectively bargained with the players’ union.

“It’s all a matter of what a guy wants to do to his body,” Indians infielder John McDonald said. “It’s a personal choice, and what people should be talking about is what guys are doing with their lives.”