Manager Bobby Valentine said Gonzalez tested out well Sunday morning and was in the batting cage hitting.
Gonzalez told a couple of reporters that the spasms originally surfaced when he bent over Friday to greet a child in a stroller while walking through a Tampa mall in which the team hotel was located.
Gonzalez worked out Thursday when the Red Sox gathered for their series against the Rays after the All-Star break.
"I was perfectly fine that day," he said. "(Friday), the more I did, the more it tightened up. Just locked up. Weird."
About an hour before Friday's game, a 3-1 Red Sox win, Gonzalez was scratched from the starting lineup and replaced by Mauro Gomez.
"I told Bobby (Friday), 'I can play if you want me to. I can get enough heat on my back, numbing pills, I can just forget about it and gut my way through it,' " Gonzalez said. "He doesn't want me to do anything.
"It's better (Saturday). They just don't want me to do anything."
Saturday's 5-3 loss to the Rays was the third game Gonzalez has not started this season. He played in 159 games last season, his first with Boston, and had played 160 games or more in his last four seasons with the San Diego Padres. The first baseman had not missed back-to-back games since becoming an everyday player in 2006.
In other Red Sox news, to make room for right-hander Clay Buchholz, who came off the disabled list for his start Saturday night, the Red Sox optioned Gomez to Triple-A Pawtucket. Gomez hit .308 in six games with the Red Sox, the first five of which he started at third base. He knocked in three runs and committed four errors.
With Gonzalez out, Brent Lillibridge drew the start at first base Sunday. He has made 14 big league starts at that position.
Punto was receiving treatment Saturday on his ankle after Ben Zobrist slid hard into him in the eighth inning Friday. Punto said he thought he'd be fine.
Also, right-handed pitcher Scott Atchison was placed on the 15-day DL (retroactive to June 14) due to right forearm tightness, and the Red Sox recalled right-handed pitcher Junichi Tazawa from Pawtucket. Tazawa was activated for Sunday's game.