DETROIT, MI - OCTOBER 18: Wide receiver Calvin Johnson #81 of the Detroit Lions during the NFL game against the Chicago Bears at Ford Field on October 18, 2015 in Detroit, Michigan. The Lions defeated the Bears 37-34 in overtime. (Photo by Christian Petersen/Getty Images)

Former 6-time Pro Bowler says “it wasn’t worth my time” about NFL tenure following sudden retirement

"...It's the definition of insanity..."

Calvin Johnson's abrupt retirement in 2015 after only nine seasons in the NFL was shocking since he was still in his prime, but the former 6-time Pro Bowler has no regrets about calling it quits early.

Johnson was in Italy recently as a guest for the Italian Bowl, and he said the reason he was content with walking away early was because he didn't think the Detroit Lions would contend for a Super Bowl at any point during his tenure.

"I did not see a chance for them to win a Super Bowl at the time," Johnson said. "For the work that I was putting in, it wasn't worth my time to keep on beating my head against the wall and not going anywhere. It's the definition of insanity."

Related: After throwing shade at Lions, Calvin Johnson makes troubling admission

Johnson admitted he was "tapped out" after nine seasons with the Lions, and he thought about going to another team, but the Lions wouldn't release him from his contract.

"I thought about (changing teams), but it's not quite like that in football," Johnson said. "I was stuck in my contract with Detroit, and they told me they would not release my contract so I would come back to them."

Here is Johnson's full press conference and all of his remarks about his nine-year NFL career.

Johnson said he could see the Lions winning a Super Bowl at some point in the future, just like the Chicago Cubs and Boston Red Sox did after many failed seasons in baseball.

Johnson is perhaps the second greatest Detroit Lions player of all-time. The greatest, Barry Sanders, also retired in the middle of his prime.

(h/t 247Sports)