Joe Judge and the Giants have an opening they did not foresee, as Aaron Wellman, the strength and conditioning coach, is leaving to fill the same role at Indiana University, his alma mater, The Post confirmed.

This came as a surprise to Judge and the Giants. Wellman, hired by Ben McAdoo in 2016 and retained by Pat Shurmur and Judge, oversaw a transformation to the entire training operation, both in the offseason and during the season. As a result, the Giants were a healthier team after Wellman arrived than they were before he came aboard.

Wellman and his wife, Shellie, are both Indiana grads and are returning to their home state. Wellman got his start in coaching at IU as a grad assistant in 1997 and took over the strength and conditioning program at Indiana a year later. He had stops at various schools, including Michigan and Notre Dame, before making his debut in the NFL with the Giants.

Why make this move so late in the hiring cycle? There was a chain reaction when Indiana’s strength and conditioning coach, David Ballou, left for Alabama. The Alabama job opened up when their longtime strength and conditioning coach, Scott Cochran, went to Georgia to work in an on-field role on special teams.

The position with the Giants falls under the medical/strength and conditioning/performance department and, as such, the hire of Wellman’s replacement will be a collaborative decision, with Judge, the front office and Ronnie Barnes, the senior vice president of medical services and the head athletic trainer, all having input.

Remaining on the staff Wellman leaves are Thomas Stallworth (assistant strength and conditioning coach), Sam Coad (entering his first season as the performance manager) and Pratik Patel (nutritionist).