The Detroit Lions are hopeful they avoided a disastrous injury.

Defensive back C.J. Gardner-Johnson suffered a non-contact injury midway through the Lions' second training camp practice Monday when he tried to weave his way through the line on a handoff to rookie Jahmyr Gibbs.

Gardner-Johnson underwent further testing Monday, though Lions trainers were optimistic the injury was not season-ending after tending to him on the field. ESPN reported an MRI showed Gardner-Johnson suffered no structural damage to his knee.

"Sad, man," said Lions cornerback Jerry Jacobs, who tore the anterior cruciate ligament in his left knee in a game against the Denver Broncos in 2021, the second significant knee injury he suffered in his career. "I can’t really have no words for it. When I seen it, I just prayed for him and you can’t really do too much because he’s down. You can’t really say nothing to someone like that going through something like that. You can say something, but it’s just not really going to feel great because he wants to be out here with us so I’m just going to pray for him and just make sure everything all right for him."

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Gardner-Johnson immediately started pounding on his right knee as he lay on the ground, and remained down for more than five minutes until two trainers helped him to his feet. He could not put pressure on his right leg and was carted off the field after teammates Jared Goff, Halapoulivaati Vaitai and Isaiah Buggs came over to offer him words of encouragement.

Gardner-Johnson signed a one-year free agent deal with the Lions in March after tying for the NFL lead with six interceptions last season and helping the Philadelphia Eagles reach the Super Bowl. He is expected to play a significant role in the Lions' revamped secondary under his former position coach with the New Orleans Saints, defensive coordinator Aaron Glenn.

Gardner-Johnson took first-team reps at safety and slot cornerback the past two days and is already considered one of the emotional leaders of the Lions defense.

"He’s got a great energy and that energy trails on to us," Jacobs said. "With all us, we’re going to miss him. Not saying it’s a big injury, I don’t know what it is, but if he got down for a couple weeks we’re just going to miss him because the energy ain’t the same without him in the room."

Fellow cornerback Emmanuel Moseley, who tore his ACL with the San Francisco 49ers last season, underwent a clean-up procedure on the knee recently and has been excused from the start of training camp. Moseley, expected to compete with Jacobs for the starting job opposite Cam Sutton, will go on the physically unable to perform list once he reports.

Despite their injury woes, the Lions have good depth at the safety and nickel positions that Gardner-Johnson plays. Tracy Walker, in his return from a torn Achilles, and Kerby Joseph, who led the Lions with four interceptions last season, have taken most of the first-team reps at safety this summer, and Will Harris and rookie Brian Branch are capable slot cornerbacks.

Harris made 10 starts and had his first career interception for the Lions last season, while Branch, a second-round pick, had a strong training camp debut Sunday.

Harris played slot corner in the Lions' first-team nickel package in a seven-on-seven period after Gardner-Johnson suffered his injury Monday, and Branch had a pass breakup later in the same period on an Adrian Martinez pass to Dylan Drummond.

"If someone goes down, another guy’s going to step up and that can be just as good as a player that actually went down," Glenn told the Detroit Free Press, part of the USA TODAY Network, last month. "That goes to show what happened with Tracy last year. Tracy goes down, we had to force Kerby to go in and play and he had some lumps early and it wasn’t easy for him, but as he continued to grow and understand, he got better. So I don’t think we have this year, one of our safeties goes down, man, we got another guy right behind him that’s ready to go. Same thing with the nickel, we got a guy right ready to go. Same thing at the corner."

Contact Dave Birkett at [email protected]. Follow him on Twitter @davebirkett.