La Stella hit an infield groundout before being lifted for pinch-hitter Darin Ruf in the fifth inning.
In other moves, the Giants transferred right-hander Anthony DeSclafani (right ankle inflammation) to the 60-day injured list and optioned outfielder Luis González to Triple-A Sacramento. Right-hander Yunior Marte was optioned to Sacramento on Sunday, and the Giants selected the contract of right-hander Mauricio Llovera.
La Stella, in the second year of an $18.75 million, three-year contract, missed time in his first year with the club due to a broken right hand and a hamstring strain. He underwent surgery in October to repair an Achilles' tendon issue, and the recovery time forced him to miss the first five weeks of the season.
Giants manager Gabe Kapler welcomed La Stella's return, saying his veteran presence bolsters clubhouse stability and resolve. La Stella's defensive versatility also gives Kapler additional flexibility in managing the lineup, and his bat adds to the team's overall fire power.
"Tommy is one of the better plate appearances in baseball right now, simple as that," Kapler said. "He has great discipline, fouls off pitches, is extremely competitive in the batter's box. He's kind of the epitome of what we want our hitters to be, make a lot of contact, drive the baseball, occasionally draw a walk here and there and keep the line moving."
Kapler also said that DeSclafani had not encountered a setback in his rehab of an ankle injury that has sidelined him since April 22. He said DeSclafani and team doctors and trainers have settled on a rehab program to gradually build back his arm and leg strength so that he's ready to fill a slot in the rotation when he returns.
"A long, slow ramp for a pitcher is the most protective thing we can do for them," Kapler said, adding that "getting him back to the big leagues healthy and strong and capable of taking down a full workload is the most important piece of this puzzle."
The Associated Press contributed to this report.