AP

There are varying degrees of voluntary when it comes to voluntary offseason workouts.

And 49ers coach Jim Harbaugh even passed out perfect attendance certificates and T-shirts to the 31 of his 90 players who made every workout this spring to help underscore the difference, and recognize the people who treated them as mandatory.

“It’s a neat thing,” Harbaugh said, via Matt Barrows of the Sacramento Bee. “You think back to when you were in school, and on the last day of school you get a perfect attendance certificate. And that’s what this is. It says something nice about you. You go put it up at home, put it in a little frame. Put it on the wall.”

Most of the players who earned the recognition were the guys who can’t afford to take a day off — the rookies, the fringe players. But 49ers linebacker Patrick Willis was in the middle of it as well. That’s a good sign for the 49ers, as one of their best players is also recognized as one of their hardest workers. And the work is doubtless hard.

“It’s a high criteria,” Harbaugh said. “It’s a very cruel, very relentless criteria. It’s perfection. It’s every practice, every meeting, every weight workout with no excuse. You could have a great excuse. But if you weren’t there — perfect — then you don’t get a certificate and a T-shirt.”

Harbaugh has doled out symbolic clothing in the past, such as blue-collared work shirts.

It’s a tangible reminder, but the best news for Harbaugh was that one of his best players bought in, which pushes everyone along.