Friday is the first day that major league rosters can be expanded from 25 players to include whomever is on a 40-man roster. But don't expect a wave of reinforcements to hit Target Field right away.

That's because factors such as injuries (significant) and Class AAA Rochester's playoff push (not as significant) make a mass call up difficult.

Twins manager Paul Molitor said Wednesday that he would like to add three players in the next few days. One of them is expected to be a catcher, as Jason Castro remains on the seven-day concussion DL with his return to action unknown.

With Castro out, Molitor wants a third catcher, which suggests the club could call up Anthony Recker, who was acquired along with Jaime Garcia in a July 24 trade. Recker would have to be put on the 40-man roster to make that happen — and Molitor hinted Wednesday that not all the planned call-ups are on the 40-man roster.

"To have a third catcher, obviously, is a big plus," Molitor said, "how you can pinch hit and not put yourself at risk late in ballgames."

Castro, meanwhile, has begun workouts and might try to swing a bat over the next couple of days. The Twins hope to have a better read on how long Castro will need Thursday.

Lefthander Buddy Boshers, who has pitched in 27 games for the Twins, is expected to be one of the call-ups.

Also consider that the Twins have six players on the disabled list — Castro, Miguel Sano, Robbie Grossman, Adalberto Mejia, Hector Santiago and Dietrich Enns. As those players get healthy, they can just be added to the roster.

Hope for Houston

Tyler Duffey lives in southwest Houston. Grossman lives in the northwest suburb of Cypress. So both have spent the past several days checking on family and friends after the devastation that Hurricane Harvey has inflicted.

Both were relieved to report their families were fine, but they know of many who weren't as fortunate.

"I have friends where their houses, cars, business have 4 feet of water inside," Duffey said.

Grossman has seen pictures of water that covers overhead highway signs. He said his parents were lucky. The water only got curb high, but a nearby neighborhood was under water.

The Twins are assisting in the relief efforts. Twins players are auctioning off autographed spikes and matching the highest bids.

At Friday's game, Twins players' wives will sell autographed baseballs, cookbooks, T-shirts and totes, with all proceeds going to the relief fund.

Injury updates

Sano will be backed off the activities he's been doing in an attempt to help him recover from a stress reaction in his left shin. Sano's recovery has been slower than expected, so the Twins hope that restricting his work will help him get over the hump. Molitor revealed Wednesday that Sano has been wearing a boot on the leg to help his recovery.

Santiago gave up one run over 2â…” innings on Tuesday in a rehab outing for Class AAA Rochester. His command was off, and he was in the mid-80 miles per hour range with his fastball.

"Obviously some rust there," Molitor said. Santiago will start on Sunday, and the Twins hope to see some progress.

Etc.

•The deadline for trades of players who have cleared waivers is at 11 p.m. Thursday. The Twins have spent the month putting in waiver claims on players they have been interested in and on players they want to keep fellow playoff contenders away from. But there are no indications the Twins were close to any moves as of Wednesday night. Any players traded after Thursday are not eligible for the postseason.

• The Twins named righthander Dillon Gee the starter for Friday, when they open a three-game series against Kansas City.