Wood struck out six and gave up two hits Monday in the Braves' 4-0 victory, a game shortened to five innings by rain.
Medlen was Gulf Breeze to be examined by Dr. James Andrews, who confirmed the right-hander will need the second Tommy John operation of his career. He was scheduled to undergo surgery on Tuesday.
Another ailing pitcher, Brandon Beachy, also was examined by Andrews. There was no word on his prognosis, but Beachy was heading to Los Angeles to get another opinion from Dr. Neal ElAttrache, the Dodgers' team physician and a specialist on elbow injuries.
''They know they're injured. It's just a matter of finding out how badly they're injured,'' Braves president John Schuerholz said. ''We're not counting on either of them. I mean, we hope that's not right, but that's the way we're planning.''
Medlen, who won 15 games last season, left a spring training game on March 9 and already said he expected to undergo the same operation he had in 2010. Beachy, who had a ligament replaced in 2012, was hoping to avoid a repeat of the operation that cost him half of that season and most of 2013.
''We're still waiting for confirmation,'' Schuerholz said.
Medlen tore his right ulnar collateral ligament while pitching against the Mets on Aug. 4, 2010, and was operated on by Andrews two weeks later. Medlen didn't pitch for the Braves again until Sept. 25 the following year.
''It's sad for them and for us,'' Schuerholz said. ''We have a really good team put together. But actually, with the patchwork quilt we've put together, with (Ervin) Santana and Gavin Floyd, who has thrown very well in camp, and Mike Minor, who has had some normal spring training stiffness, we should be OK.''
Santana, who has 105 big league wins, agreed to a $14.1 million, one-year contract last week. Santana and Minor, who reported to spring training with a sore shoulder, pitched batting practice Monday at the Braves' training complex. Floyd, recovering from elbow ligament-replacement surgery last May, is expected to miss the first month of the season.
Dan Uggla drove in three runs with a home run and a triple. His third spring training homer came in the second inning off Darin Downs, who allowed just the one hit in two innings. Uggla tripled off Kevin Chapman in a three-run third.
Evan Gattis had two hits for the Braves and scored on Uggla's triple.
Chapman gave up five hits in one inning.
BRAVES: Wood has not given up a run in four starts. He has two walks and 12 strikeouts in 14 innings.
X-rays on Braves catcher Ryan Doumit's right hand were negative. Doumit took a foul ball off his middle finger on Sunday.
Monday marked the second time Astros manager Bo Porter got his pitchers' innings by checking weather reports and moving up their work to morning.
''The last thing you want in spring training is to get your starters backed up, and then you have to try to find innings as you go along and you don't get an opportunity to get em' built up,'' Porter said.
Williams, who started 25 games for the Angels last season after beginning the season in the bullpen, threw six innings in the intrasquad game and says he's happy with either role. ''If he needs a fifth starter or a reliever, I'll do it,'' he said. ''Last season I got an opportunity to start and I did well.''