Carrasco will replace veteran lefthander Les Walrond in the Lehigh Valley rotation. Walrond was summoned to the majors after reliever Rudy Seanez was placed on the disabled list with inflammation in his right shoulder late Friday night.

Seanez sustained the injury in a tag-play collision with Washington outfielder Lastings Milledge on Thursday night.

Assistant general manager Mike Arbuckle said the organization had been considering promoting Carrasco anyway.

"We feel he's ready," Arbuckle said. "We want to see how he handles the challenge."

Carrasco is rated as the Phillies' No. 1 prospect by Baseball America. He was 7-7 with a 4.32 ERA in 20 games (19 starts) at double-A Reading.

"He's been a guy who has needed a little adjustment time as he has moved up levels," Arbuckle said. "We wanted to get him to triple-A and have him make his adjustments in August, rather than out of spring training next year."

Carrasco, a 6-foot-3 Venezuelan, drew the interest of several clubs in trade discussions last month. Arbuckle said shortstop Jason Donald and catcher Lou Marson, both of whom are playing for the U.S. Olympic team, also drew extensive interest.

Phils general manager Pat Gillick recently said that Carrasco projected as a No. 3 starter in the major leagues.

"We've got some guys who think he's a three or a four," Arbuckle said. "I think he can be better than that. I think guys mature. People forget he's only 21 and with maturity he could get better. I think he could be a legitimate No. 2."

No sleep, no problem

Walrond, who appeared in the majors with Kansas City in 2003 and the Chicago Cubs in 2006, learned of his promotion after a game in Norfolk, Va., on Friday night. He took the team bus back to Allentown, arrived at 4 a.m., packed some clothes and caught a morning flight to St. Louis.

"I'm working on about two hours sleep, but I feel great," Walrond said before last night's game against the Cardinals.

The 31-year-old lefty joined Lehigh Valley after being released by the Cubs' triple-A Iowa club in April. With Iowa, he had a 6.55 ERA in seven relief appearances. With Lehigh Valley, he was 5-7, with an International League-best 2.61 ERA in 17 starts. He was 4-0 with a 1.06 ERA in his last seven starts. In one of those starts, he struck out 17.

Walrond, who throws a fastball, changeup, slider and curveball, will work out of the bullpen.

Sunday night baseball

The Phils and Cardinals will close out their three-game series tonight. The game had originally been scheduled for 2:15 p.m., but was moved to 8 p.m. to accommodate ESPN, which has the right to move up to five of a team's Sunday games to prime time.

The Phils' Aug. 17 game at San Diego has also been moved to 8 p.m., and there is talk that games on Aug. 24 (home against the Dodgers) and Sept. 7 (at the Mets) could also be moved.