Gronk credits jigsaw puzzles with helping his mental recovery

Jigsaw puzzles have become an important part of Rob Gronkowski's routine since his retirement from the NFL.

In an interview with Reena Ninan of "CBS Sunday Morning" set to air Sunday, the former New England Patriots tight end explained how puzzles have helped with his mental recovery and stress.

"It just lowered my stress levels just the way ... I was feeling," Gronkowski said. "I (was) just ... always anxious, always going. And I just needed to finally find some downtime to just relax.

"Just started improving my ... problem-solving skills, too, on top of it. It was crazy. My brain was just clicking. It was just going. It was all on wheels."

There was some speculation Gronkowski could return to the NFL this season, but that ended in November with the announcement he'll be hosting a beach party music festival in Miami during Super Bowl weekend.