Penny complained of right shoulder stiffness after throwing a bullpen session Monday. An MRI of the right-hander -- whose fortunes reversed in the second half after going 10-2 in the first half and starting last year's All-Star Game -- showed no structural damage.
"I just don't want to go into the season not feeling 100 percent," said Penny. "If this was the regular season, I wouldn't miss it. It's just a little stiff and I don't want it to progress and get any worse and affect the next start."
Manager Grady Little said Penny would throw a bullpen session Friday and start Monday, assuming the stiffness in the front of the shoulder is gone.
"We're probably being overcautious, but we can afford that with the time we have," said Little. "The training staff doesn't think it's serious. If it doesn't bother him in his last two starts, he should be good to go for the regular season."
Penny has been pushed around in three exhibition starts this spring and has a 12.86 ERA, with 17 hits allowed, six walks and two strikeouts in seven innings. His most recent appearance was Mar. 16, when he threw five innings of a simulated game against Minor League hitters.
He is scheduled to start Game 4 of the regular season, the opener of a three-game series in San Francisco against the Giants.
Kuo, once considered the front-runner for the fifth-starter job, replaced Penny against the Mets and took a big step toward a demotion back to Triple-A.
He allowed only one hit, but was wild enough to walk four with four wild pitches working exclusively out of the stretch, even though management has suggested he winds up. He has allowed 10 walks in nine innings this spring, not counting one walk and three homers allowed in the rained out game against Boston last week.
"He's got to be better," said Little.
Between Kuo's wildness and Elmer Dessens' ineffectiveness, Little was annoyed enough to say about the pitching:
"I'm very concerned. What we're seeing right here, right now with a lot of people is a lot of assuming, maybe way too much. As we get closer to the time, it's time for some of the guys to turn it up. They're assuming they've got a position and maybe that's not the case. It's time to go to work."
Brett Tomko has taken the lead in the fifth-starter race, while Rudy Seanez is pitching like he'll make the club as a non-roster invitee. That means somebody in the bullpen won't, and that somebody could be Dessens, even though he has a $1.7 million salary.
"We'll take the best ballclub we can find," said Little.
Dessens was roughed up for three runs in two innings, including a homer by Ramon Castro. Dessens' ERA is up to 4.09, while Seanez hasn't allowed a run and only three hits with seven strikeouts and one walk in 7 1/3 innings.
More roster bids: Three players on the bubble -- Wilson Valdez, James Loney and Larry Bigbie -- continued their impressive play. Valdez went 2-for-5 playing third base to raise his average to .367, Loney went 2-for-3 to raise his average to .419 and Bigbie went 1-for-2 with an RBI to raise his average to .366. It's likely only one of the three will make the Opening Day roster. Valdez is out of options and Bigbie has an escape clause.
Balk clinic: Bruce Froemming, MLB's senior umpire, gave Dodgers pitchers a briefing on balks and an update on rules changes before the game.
Injury update: Jason Repko, healed from a groin strain, returned to game action and was tested on the bases and in the field but came away fine.
Extra hitting: Ramon Martinez and Marlon Anderson are scheduled to get extra at-bats in a Minor League game Thursday.
Happy birthday: The Dodgers' baseball academy in the Dominican Republic, Campo Las Palmas, turned 20 Wednesday. It was the first-of-its-kind facility and has since been replicated by numerous teams throughout baseball.
"Twenty years ago, Campo Las Palmas set the standard for baseball development in Latin American countries," said Dodger owner and chairman Frank McCourt. "As we renew our commitment to developing young players and bringing them up through our Minor League system, Campo Las Palmas will play an integral role in the future of the Dodger organization."
Among the long time staff is Eleodoro Arias, who serves as the director of Campo Las Palmas and has been with the club since 1985. Arias oversees the development of Dodgers prospects each year. Longtime Dodgers executive Ralph Avila joined the club in 1971 and is currently the senior advisor, Latin American scouting, actively leading Dodgers' scouting operations throughout Latin America.
Coming up: Tomko and long shot Joe Mays are scheduled to pitch against Baltimore Thursday, as is Beimel in the first of back-to-back appearances.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.