CHICAGO – Former Twins star first baseman Justin Morneau, now with Colorado, dived for a ball May 13 and has not played since.

Morneau has a concussion, and Twins fans know what that means. He has had a history of concussions going back to youth hockey, as well as multiple concussions with the Twins.

Joe Mauer said he contacted his close friend as soon as he heard about the latest episode.

"He said he was diving for a ball and it took a bad hop and he tried to react to that," Mauer said. "Just got in kind of a weird position. Hopefully those symptoms clear up and he can get back to normal."

Morneau had the 2010 and 2011 seasons with the Twins abbreviated because of concussions. Mauer's 2013 season was cut short by a concussion and led to his move to first base. So Mauer knows what is at stake.

"I talked to him a couple days ago and he was hoping it would be only a few days," Mauer said of Morneau, who won the 2014 National League batting title with the Rockies. "But it's a serious thing. It's not something you can say, 'I'll be back in a couple days.' You hope it really is a couple more days, but you don't really know."

Deep in days off

When the Twins routed Chris Sale and the White Sox 12-2 on April 30, Mauer had a single and a double off the lefthander.

The Twins faced Sale again on Saturday — and Mauer was on the bench. Mauer is batting .338 against lefties and .296 against Sale.

What's the deal?

"Kind of a big picture thing for me," Twins manager Paul Molitor said before his team's 4-3 victory. "I know we had the off days [Monday and Thursday]. We have three day games in a row, a night game, then another day game next Wednesday. It's early. Just one of those days."

Mauer insisted before the game that he was fine physically and was available off the bench if Molitor needed him. Molitor did, summoning Mauer as a ninth-inning pinch hitter against Jake Petricka with Kurt Suzuki on second. Mauer was intentionally walked.

"I told him I've come ready to play every day," Mauer said. "He said he wanted to give me a blow, so it's probably a good thing for me."

Molitor's decision came at an odd time. The Twins had two off days surrounding their two-game sweep at Pittsburgh. Mauer hit his first homer of the season Wednesday to beat the Pirates, then drove in the Twins' first run against the White Sox on Friday with a double. But Molitor has been focused on making sure he doesn't wear players down early in the season.

"He'll be back in there [Sunday]," Molitor said.

Mauer is batting .391 with two home runs against lefthander Jose Quintana, Chicago's scheduled starter in the series finale.

Arcia to Rochester

Outfielder Oswaldo Arcia leaves Sunday for Class AAA Rochester, where he will begin a rehabilitation assignment.

Arcia has missed 17 games because of a right hip flexor strain, which took longer than expected to heal. Now healthy, he is not headed to Rochester simply to get a few at-bats before returning to action. He's going to have to hit his way back to the majors.

"He needs to go down and show he's ready to come up and help the club," Twins assistant General Manager Rob Antony said. "We've gotten away from go down, get a couple of at-bats and come back up. All of a sudden the guy is 0-for-12 and not helping the team. A, we need to know that he's healthy, and B, he needs to look like he's ready to help us."

No red flags

When outfielder Jordan Schafer was placed on the disabled list, his right knee continued to bother him. So the Twins sent him to see specialist Dr. James Andrews to make sure nothing serious was wrong.

Andrews concurred with the Twins' assessment that Schafer has a sprained right medial collateral ligament. Schafer is starting to do some light rehabilitation work.