Santiago (back) left his rehab assignment with Triple-A Rochester and flew to Minnesota, the Minneapolis Star Tribune reports. "He is still feeling that tightness in his upper back," Chief Baseball Officer Derek Falvey said. "So we're going to have a follow-up evaluation and announce the details of that one once we find out."
It doesn't sound like Santiago will be able to return this season. Even if he does, he's pitched so poorly that the Twins are unlikely to use him in any significant role in a playoff race.