Rob Gronkowski is enjoying life in retirement — one piece at a time.

The former star tight end who helped the New England Patriots win three Super Bowls during his nine-year career uses jigsaw puzzles to lower his stress levels and to help his mental recovery.

Gronkowski said in an interview with Reena Ninan for “CBS Sunday Morning” that airs Sunday on the CBS Television Network that he “just wasn’t feeling like myself anymore” after retiring from playing football. He said the lifestyle caught up to him and he wasn’t enjoying playing the game.

The 30-year-old Gronkowski, who had 521 catches for 7,861 yards and 79 touchdowns, has used several methods to improve his life since his playing days, including nutrition programs, physical therapy — and solving puzzles.

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

Gronkowski, who estimates he had 20 concussions during his playing days, realized that doing puzzles was also helping him mentally, particularly with problem solving.

“It was crazy,” he said. “My brain was just clicking. It was just going. It was all on wheels.”

HEY, ROOK!

The Minnesota Vikings have four draft picks playing key roles on offense, starting with center Garrett Bradbury.

Though the first-rounder from North Carolina State has had his share of welcome-to-the-NFL moments this season, Bradbury has shown steady improvement at a challenging position. Just ask quarterback Kirk Cousins, who sent an encouraging text message to the rookie on Tuesday, the day after Minnesota’s loss at Seattle. “He’s done a really good job for how much we’ve put on him,” Cousins said.

Cousins had a greater purpose in mind with his message, too, recalling a pick-me-up he received as a rookie for Washington when coach Mike Shanahan summoned him to his office for a positive review during spring practices. “Going back to work that day and the next day and the day after that, to have confidence and belief that you’re doing something right and you’re going places, it makes all the difference,” Cousins said. “So I try to think back, `Who could I be Mike Shanahan for in a way and encourage them?’ Sometimes it’s just a text or just walking off the field and telling somebody. You’re getting coached left and right and all the things that you need to do better, but you also need to hear when you’re doing things really well. I think people need to hear that. “

NOT AN ASTERISK

To Tennessee Titans coach Mike Vrabel, there’s really no significance for himself or even the history books of being the next-to-last team to play the Raiders in Oakland-Alameda County Coliseum.

“When I’m old and retired sitting around, I’ll say, `You know, the last game that they played in Oakland Coliseum? I coached in the one before that,’” Vrabel said with a heavy hint of sarcasm. “Not really sure what the significance is. ... You know the last game? I coached in the one before that one.”

Vrabel did play at Oakland during his 14-year NFL career as a linebacker. He said the dirt infield from baseball always made playing in such stadiums unique.

This visit comes well after the Oakland A’s wrapped up the baseball season.