Rob Gronkowski returns to practice, Tre' Jackson absent

(Foxboro, MA, 01/11/16) New England Patriots tight end Rob Gronkowski receives a catch during practice outside Gillette Stadium on January 11, 2016. Staff photo by Matt StoneFOXBORO -- Patriots tight end Rob Gronkowski returned to practice today after missing yesterday's workout for unknown reasons. The Pats will release their first injury report of the week this afternoon, but Gronk hasn't been listed for injury reasons since Week 14, so it's possible he won't be on it.

Right guard Tre' Jackson missed today's workout. Jackson hasn't been absent since Nov. 14 when he missed two weeks of workouts due to a left knee injury. He was present in the locker room before the workout, so it's unclear…