BAL@ATL: Venters tosses scoreless ninth vs. Orioles

SAN FRANCISCO -- Jonny Venters' optimism turned to discouragement on Thursday when he felt left elbow discomfort while throwing off a mound for the first time since receiving a platelet-rich plasma injection on April 2.

Venters threw approximately 10 pitches before cutting his bullpen session short at AT&T Park before the Braves' series opener with the Giants. The left-handed reliever was planning to throw at least 20 pitches.

"It just wasn't as comfortable as I wish it would have been," Venters said. "We'll see what tomorrow brings and we'll go from there."

When Venters was able to throw off flat ground without any discomfort over the past week, he knew his first test would come when he put some added stress on his elbow by throwing on a downward plane off a mound.

"It was just a different stress than you put on it when you throw off flat ground," Venters said. "It might be one of those things where it's got to get used to throwing off a mound again. It didn't feel great. But we'll see how it feels tomorrow."

Venters battled elbow discomfort during the final two weeks of Spring Training and received the PRP injection after being evaluated by Dr. James Andrews. MRI exams were inconclusive because Venters had already undergone Tommy John elbow ligament reconstruction surgery. Andrews performed the procedure in 2005.

Venters rested his arm for four weeks after receiving the injection, which is intended to stimulate the healing of bone and soft tissue. He is hoping his latest setback was simply a product of normal soreness. But it did not seem to be a good sign when he confirmed he felt discomfort immediately after starting Thursday's mound session.

"I was putting something on it for sure," Venters said. "The ball was coming out decent. It just didn't feel very good."

Venters was one of the game's top relievers while posting a 1.89 ERA and combining to make a Major League-high 164 appearances during the 2010 and '11 seasons. He battled elbow discomfort last year and spent two weeks on the disabled list in July.

Fredi stepping away for daughter's graduation

WSH@ATL: Gonzalez discusses Hudson's memorable night

SAN FRANCISCO -- Braves manager Fredi Gonzalez will miss Friday and Saturday's games against the Giants while attending daughter Gigi's graduation from Georgia Southern University.

"You've got to do it," Gonzalez said. "I'm so proud of her."

With his daughter's graduation scheduled for Saturday at 9 a.m. ET, Gonzalez could not manage Friday night's game and then travel cross country in time to be present for the ceremonies, which will likely conclude four or five hours before the Braves begin Saturday afternoon's game in San Francisco.

Gonzalez will fly from San Francisco to Atlanta early Friday morning and then catch a connecting flight to Savannah, Ga. before driving another 45 minutes to Statesboro, Ga. He will fly back to San Francisco Saturday night and be present for Sunday's series finale against the Giants.

"I got a text from [Gigi] the other day saying this degree is yours and mom's for helping me get through college," Gonzalez said. "I'm real excited to see her."

Carlos Tosca will serve as Braves manager on Friday and Saturday. Tosca went 191-191 as Toronto's manager from 2002-04. He has served as Gonzalez's bench coach during each of the past seven seasons.

Worth noting

• Evan Gattis got a taste of playing the outfield within the smaller confines of Cincinnati's Great American Ball Park this week. But the Braves will wait until Saturday to put the rookie catcher back in the outfield. Gattis will get used to San Francisco's larger outfield while shagging fly balls during batting practice on Friday and Saturday.

• Jason Heyward began his Minor League rehab assignment by going hitless in five at-bats with Triple-A Gwinnett in Thursday morning's loss to Pawtucket. Heyward, who has been sidelined since undergoing an appendectomy on April 22, will continue his rehab assignment with Gwinnett through this weekend. The Braves do not plan to activate him from the disabled list before Monday.

• Brandon Beachy completed his last live batting practice session on Thursday. If all goes well during his bullpen session on Monday, Beachy could begin his Minor League rehab assignment on Wednesday or Thursday. Beachy, who is returning from Tommy John surgery, will make at least six starts before possibly rejoining Atlanta's rotation in the middle of June.