ALLEN PARK, Mich. -- Every day, the Detroit Lions' coaches remind their players of the same thing during offseason workouts.

Watch where you’re going. Avoid collisions. Do your best not to injure one of your teammates.

Many of the Lions players are competing for job and training camp roster spots and depth chart places throughout OTAs and minicamp. They also must realize when it comes to what happens in the fall, it won’t matter at all if the players they are competing with are unable to be on the field with them.

This was hit on even more dramatically this week when Dallas lost linebacker Sean Lee for the season with an ACL injury. The injury – and injuries always happen in football – could be crippling for the Cowboys' defense and leaves them without one of their best playmakers.

“Stay off the ground,” linebacker Stephen Tulloch said. “Just run around. Stay off the ground.”

For the most part during Detroit’s open OTA practices, the Lions have managed to do this. Of course, when there have been collisions, it has involved receiver Calvin Johnson – who ran into players knocking him to the ground in both open practices.

Losing Johnson, who is healthy again after knee and finger injuries affected him last season, would be at least as damaging to Detroit as losing Lee will be to Dallas.

So protecting all players – especially the team’s stars – is something that becomes almost as paramount as implementation and actual workouts. Yes, injuries will happen, but every team in the NFL needs to make sure if they do, they don’t come on something that could be completely avoidable.

“We talked about it [Wednesday], just making sure we are doing the best that we can to take care of each other,” quarterback Matthew Stafford said. “It’s that time of year when guys are full of energy and trying to make plays, trying to impress coaches and do all that kind of stuff.

“You have got to make sure at the same time that we’re taking care of each other and learning as we go.”

Stafford said they are reminded about that every day.

It is a difficult barrier, though, as rookies and bottom-of-the-roster players and free agents fighting for spots have to try to make positive impressions without any negative consequences. Those players can occasionally get too excited, bounce around too much.

When it happens, it is usually wiped out quickly.

“The veterans,” center Dominic Raiola said, “take care of that.”

They are the ones who know, after all, how long a season can be and how injuries can derail the season for any team in the NFL.