Martin posted 1.35 ERA in eight appearances this spring with seven strikeouts and two walks over 6 2/3 innings. Stewart hit .279 with three home runs and four RBI in 43 plate appearances.
Gallo, 21, hit .250/.333/.469 with two homers and six RBI over 32 at-bats this spring.
Williams said Rendon will continue to rehab the injury, but delivered the bad news that Rendon will begin the season on the disabled list. Williams said Rendon has a week-to-week type of injury, and sources told CBSSports.com Baseball Insider Jon Heyman that Rendon could be back in three weeks.
General manager Mike Rizzo did not put a timetable on Rendon's return.
“It's positive news,” Rizzo told Heyman. “All three (doctors) agreed. There's nothing seriously wrong, and it should remedy itself. Some turn the corner quickly and with other guys it takes a few weeks. But he will be fine.”
Yunel Escobar is expected to fill in at third base during Rendon's absence, which means Danny Espinosa will likely replace Escobar at second base. Dan Uggla could also be an option, if he makes the Opening Day roster. Ryan Zimmerman is not expected to move back to third base with Rendon sidelined.
Johnson's versatility helped earn him the spot--he can play three infield positions as well as the outfield. The decision to keep Johnson could be a bad sign for Joey Terdoslavich, who was believed to be competing with him for a bench role.
Chris Johnson was struck on the hand and had it wrapped as he left the ballpark Wednesday. Kelly Johnson was sore after being hit on the back of his right arm.
Gallo, who was the team's first-round draft pick in 2012, hit .250 in 15 games this spring with two home runs and six RBI. Alfaro hit .313 with four RBI in 16 plate appearances while Mazara hit .286 in seven at-bats.
Terdoslavich sprained his left wrist while diving to make a tag on March 21.
"It’s just weird the way it happened, just kind of a freak thing," Terdoslavich said, per the Atlanta Journal Constitution. "But a wrist and hand with a hitter is just like a pitcher with a (sore) elbow or shoulder. You don’t want to have it linger all year."
Terdoslavich is hitting .278 this spring. He's competing with Kelly Johnson for a bench spot on the Braves' roster.
Kelly will also see some time as the emergency catcher.
"Just be a guy who uses all those gloves he's toting around all the time," manager Mike Matheny said.
Kelly is hitting .194 this spring with a double and a triple in 36 plate appearances.
"It feels a lot different," Olt said of this season versus last year, per MLB.com. "I was able to go up there last year and learned a lot of things. I feel I'm back to the player who can really compete instead of the player who you hope is ready and you hope the swing is there. It's a lot different feeling, a lot less stressful."
Olt is having a decent spring at the plate, batting .279 with a .392 on-base percentage, .558 slugging percentage and .950 OPS in 19 games. It's a nice turnaround after batting .160 in 89 games in the majors last season.
"I had two crazy years and a lot of things happened to me," said Olt of some injury issues. "Now I feel it's in the past, and I have a new outlook on baseball and a new outlook on my career. I used to be one of those [top prospects like Bryant] -- and you forget about that. I feel myself becoming that guy again, and it makes baseball fun again."
"I was never concerned about that, because he's always been a guy that people have turned to and loved being around," Girardi said. "But I've been impressed by the way he's played and the way he has been able to contribute."
Rodriguez has hit .324 this spring with three home runs and four RBI in 37 plate appearances.