It has to start with the physical. Before the Detroit Lions -- or any other NFL team -- can really consider signing linebacker Zach Orr and bringing him onto a football team, it really must begin there. And teams have to be comfortable enough with the knowledge that any conversation about hiring Orr could end there, too.

This isn’t about returning from a broken leg or a torn ACL or a busted-up shoulder. The reason Orr retired in January, because of a congenital spine and neck condition, is more serious than that. Doctors at the time told Orr the first cervical vertebrae at the top of his spine never fully formed, a condition they said could put him at a greater risk of paralysis -- or death. Orr said Wednesday the condition is very rare and that he has been told it carries no additional risk. Yet considering the sport he plays -- and the position, which often requires him to run into another player at close to top speed -- is a potentially scary situation for everyone involved.

For the player. For the coaching staff. For the front office.

So while Orr may want to play, any possibility of it happening has to start with a team’s own doctors and that physical -- a physical Orr didn’t believe he would pass when he retired in January. Back then, he said, “if there’s some miracle way or some miracle treatment where I can play the game again, I promise you I’d be the first one to grab my cleats, start back training, and find a way to get back out there.”

It’s not clear whether there’s been a real change in his condition. Orr said he discovered through consultation with more doctors that he isn’t at any higher risk for paralysis or death than any other player. That might be true, but that’s something a team will need to confirm before choosing to sign Orr.

Orr is scheduled to visit Detroit on Thursday, according to ESPN Insider Dan Graziano, and the team is one of at least eight that have inquired about him after he announced he was considering a return to the game. All of those teams will have to consider the risk involved and whether it is worth it for everyone involved.

If the Lions, or another team, decide to clear him, he’d be a valuable addition. There’s no question Orr has the talent to play, after the 25-year-old registered 130 tackles, three interceptions and two fumble recoveries last season. His desire shouldn’t be questioned, either, considering what could potentially happen to him.

For the Lions, Orr would fill a need pretty fast. Detroit’s linebackers are still in question even after the team spent a quarter of its draft picks this year on improving the position, with Jarrad Davis in the first round and Jalen Reeves-Maybin in the fourth round. Davis is expected to be the team’s starting middle linebacker. Reeves-Maybin will likely start out on special teams but could mature into the team’s weakside linebacker.

But neither one has played in an NFL game yet.

Of the linebackers who have played in an NFL game, there are questions surrounding all of them. Tahir Whitehead, last year’s middle linebacker, missed all of OTAs and minicamp with an injury, and how he’d fit as a weakside linebacker remains a question. Paul Worrilow was a strong tackler in Atlanta, but lost his starting job last season. Neither has shown superior coverage skills. Antwione Williams is young and might be a better fit at Sam, where Whitehead could end up playing. Brandon Copeland is better suited as a defensive end. And an Orr signing would make the room much more competitive -- potentially pushing Whitehead, Worrilow or Williams to the roster bubble.

So there’s no question that Orr could help. He could end up being an immediate starter. That should be attractive for the Lions. It should be attractive to Orr. But both have to weigh the same issue when they are talking: Is the potential benefit worth the risk?