I'm guessing Santana is given a QO this offseason, and there is a distinct possibility he takes it. If he does accept it he's obviously in the rotation. If he doesn't accept it Wren will take the pick and go sign someone else.
Expect Wren to do what Wren always does: gather as many options as possible on a budget. He will sign a FA guy (or Santana) that can slot right into the middle of the rotation, bring in a scrap heap starter like Harang or Garcia that he can hide in AAA if needed, bring back the injured guy(s) on the cheap as insurance policies that will be ready a couple months into the season, and let the young guys in the minors also throw their hat in the ring and see if any of them earns a spot.