DENVER -- Cardinals pitcher Brad Penny encountered a setback on Tuesday in his rehabilitation from a strained right lat muscle. And while the discomfort that Penny experienced is close to the original injury, it seems that it may be something different from what landed him on the disabled list in the first place.

Penny got a good number of throws in before he felt something. He threw a normal pregame warmup, took some long-toss, and simulated an inning in the bullpen at Coors Field with a hitter standing at the plate but not swinging. When Penny came in from the bullpen to the main mound on the field and got ready to face hitters, he felt something and stopped throwing.

Penny was not available to speak with reporters, but it seems that the issue on Tuesday was less his back, where he initially injured himself, and more in his right triceps.

"[After the bullpen work], he took a break, came out to the field, started warming up to face some hitters, and he felt some tightness in his triceps," pitching coach Dave Duncan said. "So as a precaution we shut him down."

The exact severity of the injury will remain unknown until at least Wednesday. Penny left Coors Field and was scheduled to return to St. Louis on Tuesday night. He will be examined by the team's orthopedic staff on Wednesday.

"I'd characterize it as a setback," said assistant general manager John Abbamondi. "Hopefully, a modest one, but I don't know. We're going to send him back to St. Louis. He's going to fly back tonight and be evaluated by our doctors there tomorrow."

Penny was on track to make a Minor League rehabilitation start on Sunday if Tuesday's throw had gone well. He has not pitched in a game since May 21.

"It's a big negative," manager Tony La Russa said.

Holliday bound for HR Derby

DENVER -- Cardinals outfielder Matt Holliday might not seem like the most obvious choice to participate in the State Farm Home Run Derby, unless you've ever seen him take batting practice.

In games, Holliday is a high-average, line-drive hitter with solid but not exceptional home-run power. In batting practice, he puts on a show like few players in the game. He'll be participating in this year's Derby, and it should be worth watching.

"I got a chance to do it in '07, and it was fun," said Holliday. "My kids are getting older, they know what it is, and they were like, 'Do it! Do it!' I think it should be fun."

Holliday's sentiments echo those of Albert Pujols a year ago. Pujols acknowledged in 2009 that part of the reason why he participated in the Derby was that his son, A.J., urged him to do so. Pujols, however, reiterated on Tuesday that he will not be a part of this year's event.

Holliday expressed little concern about the potential for injury or for his swing getting out of whack. He enjoyed a huge second half in 2007 after swinging away in San Francisco.

"It shouldn't be too hot," he noted, adding with a smile that, "it could be as little as 10 swings."

Baby 'Birds

Allen Craig doubled and hit a grand slam, but David Kopp and Renyel Pinto had rough games on the mound in Triple-A Memphis' 11-6 loss to Round Rock on Monday. ... Tommy Pham doubled and walked in Double-A Springfield's 3-2 loss to Midland. ... Class A Palm Beach was rained out. ... Eric Fornataro walked four batters but allowed only one run on three hits over five innings in Class A Quad Cities' 5-1 win over Burlington. Ryde Rodriguez singled, doubled, scored and drove in a run, and Matt Adams homered. ... Nick Longmire went deep again for Class A short-season Batavia, which beat Tri-City, 9-6. Audry Perez had three hits and four RBIs. ... Cody Stanley, David Medina and Romulo Ruiz all hit home runs, and Trevor Rosenthal pitched five shutout innings to help Rookie League Johnson City beat Danville, 7-5.

Perez, 21, wins player of the day honors. The right-handed-hitting catcher singled three times in Batavia's win, and on the year, he's batting .410 with a .467 on-base percentage and a .487 slugging percentage. Perez signed with the Cardinals as an undrafted free agent in 2008.

Worth noting

The Cardinals' rotation for the last week before the All-Star break has taken shape. Following Blake Hawksworth's start on Tuesday, it will be Jaime Garcia on Wednesday, Chris Carpenter on Thursday and Adam Wainwright on Friday. Jeff Suppan gets the Saturday game in Houston, while Hawksworth pitches the last game of the first half on Sunday at Minute Maid Park. ... According to the Cardinals' media relations department, Yadier Molina will be the first Cardinals catcher to start in consecutive All-Star Games since Walker Cooper in 1943-44. ... Tuesday night's first pitch was pushed back 30 minutes due to threatening weather in the area around Coors Field.