Max Kepler played both games of the day-night doubleheader in Cleveland on Saturday but has not been in the lineup since. He continues to have discomfort in his shoulder, so the club sent him for more tests Monday to make sure there's nothing serious going on.

"We just want to recognize that he's got some soreness and played a doubleheader the other day and came up big for us in those games," Twins Chief Baseball Officer Derek Falvey said. "That led to, yesterday, a little bit of time down and some soreness. Today, we'll take an extra day here and see how he responds."

The soreness is in Kepler's shoulder area but closer to his scapula. Twins manager Rocco Baldelli said the recent round of tests came back clean, and now it's a matter of the soreness subsiding enough for Kepler to return to the lineup. He described the injury as a rhomboid muscle strain.

Kepler is batting .252 with 36 homers, 90 RBI and 98 runs scored, so he has a couple of milestones to reach.

"He's definitely doing better, though," Baldelli said. "He came in today and already told multiple people that he was feeling better, but it's not going to be something where as soon as he says, 'I'm doing well,' we're going to rush him back out on the field. We're going to make sure that he's able to do everything without feeling anything and going through a full workout on the field."

Kepler looked upbeat as he moved through the clubhouse Tuesday.

"It's coming along," said Kepler, who added that he's received several treatments. "I should be back soon."

It's unknown how soon that will be.

"For me to give you some sort of opinion on this would be a complete guess so I'm not going to do it," Baldelli said, "but like I said, the fact that he's not coming in saying, 'It's the same. I still feel it the exact same way I did a couple days ago,' he's not saying that. He's saying it's doing better."

Next center fielders up

The Twins have used seven different center fielders in a season in which they hoped Byron Buxton would play most of the innings. But injuries to Buxton and other developments have led to several adjustments.

Kepler has played in 60 games in center, and Jake Cave 20. As injuries mounted, the Twins exhausted their center field depth in the system. In recent weeks they called up Ian Miller, who was acquired from the Mariners organization a month ago. When Buxton had season-ending surgery last week, they dealt for minor league outfielder Ryan LaMarre from Atlanta.

In recent games, the Twins have used LaMarre and LaMonte Wade while waiting for Kepler to mend.

Wade hit his first major league homer Sunday against Cleveland, and LaMarre opened the scoring Tuesday with an opposite-field blast.

"We've needed them both, for sure," Baldelli said. "To have a couple of extra guys who can play in the middle of the field, it's very valuable. It's very helpful when making a lineup."

Bonus kicks in for Perez

When Martin Perez got the first out of the third inning Tuesday, it gave him 155 innings on the season. That triggered another performance bonus of $100,000 in his contract. Perez also received a $100,000 bonus once he reached 135 and 145 innings. Perez, whose base salary is $3.5 million this season, also can get $100,000 bonuses if he reaches 165 and 175 innings.

The Twins hold a 2020 option for $7.5 million on Perez, but that increases to $8 million if he reaches 170 innings.