Deshea Townsend played in 191 NFL regular-season games. Only six Alabama alumni have played in more.

Now the defensive-backs coach of the Detroit Lions, Townsend will be sending out another former Crimson Tide cornerback for his first NFL game on Sunday night.

Selected by the Lions at No. 24 in the NFL Draft on April 25, Terrion Arnold is listed with former Auburn standout Carlton Davis as the starting cornerbacks on the Detroit depth chart for the season-opening game against the Los Angeles Rams.

Arnold said Townsend and defensive assistant Jim O’Neil had the book on defensive-back play that had gotten the new-look Lions secondary ready for the season.

“I kind of credit Deshea and J.O.,” Arnold said on Friday. “They do a great job in our meetings. If we see a play, we have to communicate right then. And we also have this thing called a fine book, so, I mean, it’s just about holding each other accountable. It’s just one of those things, like, if you mess up on this play, hey, we all calling you out on this, and it just kind of jells with our chemistry and it jells with us seeing different looks and things.

“And the main thing they do is they allow us to go out there and play our game. I mean, they’re going to coach us to have the right alignment, right technique. But at the end of the day, we brought you guys in for a specific reason, and I’m not going to hinder you from doing that, so they do a good job of that.”

Arnold said his name had found its way into the fine book while he prepared for his first NFL season.

“He’s very, very strict on it,” Arnold said. “Just for loafing, which that’s conduct detrimental. I mean, you can’t loaf. And I’ve got fined for not punching at the ball, so, I mean, they do a very, very good job of just trying to make it intense. And it’s kind of becoming muscle memory, so even in the game, if I see a ball on the ground and you just pick it up, it might just happen to be a fumble and you think it’s an incompletion, so just trying to reiterate muscle memory.”

The top four cornerbacks on the Detroit depth chart are new to the team, with Davis joining in a trade with the Tampa Bay Buccaneers, Amik Robertson coming aboard in free agency and Ennis Rakestraw Jr. joining as the second-round draft pick.

Brian Branch, one of the starting safeties, played mainly slot corner as a second-round rookie from Alabama last season.

“He’s a playmaker,” Arnold said about Branch, “and he’s just one of those guys, when he goes out there, you never really know what he’s going to do, but you know there’s going to be something exciting. So with him being at safety, it gives him a chance to show off his versatility, stay in the middle of the field.

“But even when he kind of gets a full steam ahead at running downhill, that’s going to be pretty scary. I just know, like, if I’m in the middle of that play right there, I’m probably going to back up. So, yeah, I’m going to let him take that tackle on by himself.

“But just him being over there at safety, it’s been fun to watch and interesting to see because it kind of shows off his versatility, shows off his range. And then B.B. is a very cerebral player. Like I always just reiterate to him, like, man, just trust yourself. You can feel it happening, so just go out there and make the plays, so I think people are going to get to see his full toolbox and his playmaking ability.”

Arnold will debut against the Rams in the Week 1 Sunday night game, which NBC will televise at 7:20 CDT.

“I went to Alabama,” Arnold said, “so I feel like this is really just another game.”

But Arnold does expect to be in the spotlight. He figures Rams quarterback Matthew Stafford will test him early.

“I don’t really know what’s going through Matthew Stafford’s head,” Arnold said, “but I know guys like Aaron Rodgers. They prey on rookies like that, so my main thing is just be alert at all times.”

Los Angeles has one of the NFL’s best wide-receiver duos in Puka Nacua and Cooper Kupp for Arnold’s debut.

“No. 1 is their coach,” Arnold said. “Sean McVay, he does a great job of dressing up his plays. He has a lot of motion before, and he can kind of get your eyes when really they’re just running simple, basic routes.

“But guys like that, they do a very, very great job of controlling the tempo. They might not look like guys who would just line up and beat you one-on-one, but they know how to attack your weaknesses, know how to win at their leverage, and they have a great chemistry with their quarterback, so you just really have to stay disciplined when you’re guarding guys like that.”

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Mark Inabinett is a sports reporter for Alabama Media Group. Follow him on Twitter at @AMarkG1.