ARLINGTON – Rangers pitching coach Mark Connor does not throw around praise lightly, but in discussing Scott Feldman's rapid ascent as a starting pitcher, he sure did pick a doozy of a comparison.

Scott Feldman, meet Roy Halladay.

Feldman's success as a starter – all three of his major league starts have been quality starts – is due in large part to the addition of a fastball that naturally cuts toward left-handed hitters. The cutting fastball gives him a weapon against lefties to go with the sinker he had before he was converted from a side-arm reliever to a traditional-throwing starter.

"He's essentially got two fastballs, one that goes one way and one that goes another way," Connor said Saturday, a day after Feldman pitched six scoreless innings. "There's another guy in this league that does that, and he's got a Cy Young Award. Halladay. Hitters almost have to guess which one he's throwing."

Halladay also has a strong curve ball, and the breaking pitch is something Feldman is still grasping, but Connor's point was clear: A pitcher with two fastballs that look the same but move in different directions can be dangerous.

The Rangers initially called Feldman up because they had a shortage of arms. His first three starts have put him in position to claim a more permanent spot. The Rangers have three starters on the disabled list: Luis Mendoza, Jason Jennings and Brandon McCarthy. While only Mendoza is close to returning, Connor indicated that Feldman has pitched his way into long-term consideration.

■ Injury update: The field was busy before batting practice with various Rangers in differing degrees of recovery.

Mendoza (sore shoulder) threw about 45 pitches in a simulated game with no problems. He was particularly pleased with his sinking fastball.

"I wasn't really able to get on top of it because my shoulder was sore," Mendoza said. "But today it was strong, and it felt good."

He will throw a bullpen session Monday and then begin a rehab assignment in the minor leagues that will include at least two starts.

Third baseman Hank Blalock (partially torn hamstring) ran at about half-speed for the second consecutive day and took grounders for the first time. The Rangers have set no timetable for his return.

■ Briefly: INF Joaquin Arias played shortstop Friday for Triple-A Oklahoma, the first time he's played his natural position since last summer's shoulder surgery. He was back in the lineup at second base Saturday. GM Jon Daniels said Arias will play short only occasionally as he continues to build arm strength.