Mauer suffered a concussion when he took a foul ball off the catcher's mask. He experienced dizziness during batting practice the next day and landed on the seven-day concussion disabled list. He was cleared for light exercise in late August and there was initially some thought he could return to the lineup in early September.
His concussion symptoms, however, returned when his workouts ramped up. After a brief break, he resumed workouts recently, but the Twins decided not to rush him back. Minnesota has been out of playoff contention for months and with seven games remaining in the regular season, there wasn't much benefit in rushing Mauer back. Instead, he can take the entire offseason to ensure none of the concussion symptoms persist.
The injury will not force a position change, at least immediately. Mauer said he plans on remaining at catcher next season, according to Rhett Bollinger of MLB.com.