NEW YORK -- After he was selected in the first round of the 2007 First-Year Player Draft, left-hander Ross Detwiler was told by the Nationals that he had to change his mechanics on the mound.

The team didn't like that Detwiler was pitching across his body. Instead, the Nationals wanted him to throw the ball on a straight line. By pitching their way, Detwiler would be able throw more pitches on the inside part of the plate against right-handed hitters and prevent an injury to his arm.

Detwiler tried it the Nats' way, but the results were mixed. In his first two professional seasons, Detwiler was 10-10 with a 4.58 ERA. This past Spring Training, Detwiler had a tough time getting batters out, giving up five runs and walking seven batters in 5 1/3 innings in Grapefruit League action.

"The new way wasn't really working," Detwiler said. "I was getting hit a lot. I went back to what was comfortable. It made me relax a lot."

The old way of pitching earned Detwiler a promotion to the big leagues in May. He feels he is able to throw his offspeed pitches for strikes more often.

Manager Manny Acta said the Nationals have no intentions of changing Detwiler's mechanics unless he is in a serious slump.

"We like him the way he is right now," Acta said. "He has a learning curve, making adjustments. He has the privilege to learn up here. We like the progress he has made the last three or four months. We feel this guy could be a middle-of-the-rotation type of guy -- a very solid one for us.

"We are not going to tinker with his delivery for now because he is having success. We'll see how far it takes him."