SAN FRANCISCO – Patrick Bailey stood outside his locker Monday night with an ice pack wrapped in tape around his right torso, smiling and giggling.

The Giants’ catcher rarely pitches in the field before games; he prefers to do his preparations in the batting cages while preparing with the evening’s pitcher. But he changed his routine before the series opener against the White Sox by incorporating some early swings in the field, and felt some discomfort in his side afterward.

Bailey was removed from the Giants’ lineup before the first game of the series and was placed on the 10-day injured list on Tuesday after an MRI revealed a strained right oblique muscle. Jakson Reetz was recalled from Triple-A Sacramento to back up Curt Casali, who made his second consecutive start behind the plate.

After downplaying the problem as “very, very minor,” Bailey was asked about the circumstances that led to the injury.

“I think you know the answer to that,” he grinned.

Bailey’s loss is a bitter blow for a team that entered Tuesday 3.5 games out of a playoff spot with 35 games left to play. Frustratingly, he found himself in a similar slump at the plate in the second half to the one he faced at the end of his rookie season, when he spoke openly about the toll a 162-game schedule took on his body and the steps he took in the offseason to address it.

His problems since the All-Star break this season are not so easy to explain.

“Last year you could see him starting to fade a little bit,” hitting coach Justin Viele said. “He seems stronger (this year). He’s still hitting the ball hard. He’s still in his at-bats, even if it doesn’t always look like it. I just think there’s a point where you’re not getting hits and you’re not getting rewarded and you’re just like, ‘Are you kidding me?'”

“After playing with him, sometimes you think, ‘I just can’t believe it was another 0-fer, even though I thought my swing was good, I hit two balls hard.’ When something like that happens, there’s just not much to say. It’s a shame, because he does everything right.”

Only two of Bailey’s seven home runs last season came after the calendar turned to July, and this year he hasn’t hit the same total since his solo home run in a two-hit, three-walk performance against the Blue Jays on July 10. He was batting third as a designated hitter that day, and the performance boosted his batting average to .280, his on-base percentage to .356 and his slugging percentage to .430 – an OPS of .786 that ranked him eighth among 16 major league catchers with as many plate appearances.

He had a few more multi-hit games before the All-Star break, and since then, in 27 games, he’s had 11 hits — two for extra bases — in 96 at-bats with 24 strikeouts and five walks. His batting line of .115/.157/.135 translates to an OPS of .292, the lowest of 16 qualified catchers during that time. (Top of the list? Joey Bart’s .970 mark.)

For further context, the only catchers with an OPS that low over a 27-game span this season are Martin Maldonado of the White Sox and Alex Jackson of the Rays. Maldonado, 38, has a career batting average of .203 with a .404 OPS this season, and Jackson has a .135 average and a .460 OPS in 289 career at-bats.

However, the Giants do not believe fatigue is a factor.

“He’s telling me right now that he wants to play every game,” manager Bob Melvin said. “If that’s possible, he’s definitely trying to make it happen. …

“He’s had some really good at-bats the last couple of games. Before that, it obviously wasn’t pretty, but there were a lot of lineouts and his at-bats weren’t always perfect. At the beginning of the year up until probably halfway through, his workload was OK compared to most in the league. I really don’t think that has much to do with it.”

Bailey has caught 730 innings this season, eighth-most in the major leagues, and had started 91 of the Giants’ 126 games before Monday. After losing weight last season, he changed his diet this spring to endure the rigors of a full season, and it appears to have paid off.

Over the course of his career, Bailey has put 40.7% of his ground balls in play while being limited to soft contact 12.7% of the time. In the final month of last season, when he was batting .121, those rates jumped to 61.1% and 27.2%, respectively. In other words, he’s gotten a lot of easy outs in the ground.