"It's something that I just heard about for the first time a couple days ago," Molitor said. "It's something where we talked about pitching through it or backing him off for one start. We thought that was the best option for how much he's been out there this year. It gives him a little extra time for it to get better."
Molitor isn't sure if the thumb issue is a reason for Santiago's recent struggles, because the injury wasn't disclosed until recently.
"It's more of a gripping thing, enough to where we think skipping a start will be good for him," he said. "You're hoping for a good finish here. I'm sure he's not pleased with how it's gone here. Maybe that's been a part of it, and why he didn't disclose it until now. I don't know how long it's been, but it's been there. I don't know if it's been inhibiting, but it was enough where he wanted to let us know about it."
With Santiago out, Dean will make his first start with the Twins since June 17. Dean has been pitching in relief, allowing four runs in seven innings over his last three appearances. He tossed a scoreless inning in Tuesday's 8-3 loss to the Tigers, so he won't be fully stretched out heading into the outing, but the Twins have a 13-man pitching staff.
Rhett Bollinger has covered the Twins for MLB.com since 2011. Read his blog, Bollinger Beat, follow him on Twitter @RhettBollinger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.