DETROIT -- Kerron Johnson's injury appears to be minor, but concern is growing for Jamal Agnew.

The Detroit Lions' All-Pro punt returner suffered a knee injury in the second half of a 31-23 win Sunday against Green Bay. He writhed in pain on the field, then was eventually helped to the sideline before being carted to the locker room.

Detroit does have a bye next week, which gives Agnew extra time to rest. But the injury could be serious enough that an extra week won't matter.

"We'll find out when we get that evaluated," coach Matt Patricia said after the game.

Agnew has seen his role grow this season, logging 106 of a possible 241 defensive snaps in the first four weeks of the season. He is Detroit's top slot corner, plus one of the league's finest return men on punts. He has struggled on kick returns, though, and was replaced by Ameer Abdullah against the Packers.

He wasn't the only player to go down for Detroit, nor even the only defensive back. Darius Slay was also shaken up and evaluated for a leg injury, but returned. Throw in the loss of Tavon Wilson, who didn't play because of a back injury, and that Quandre Diggs is playing with a cast on his arm, and the bye is coming at the right time for Detroit's banged up secondary.

The same could be said of Johnson, the rookie phenom who entered the Packers game sixth in yards per carry, then ripped off another 70 yards on just 12 carries. That's 5.8 yards a pop.

But he also tweaked his ankle on a second-half run, and departed the game early. He later said he could have played if needed, though, indicating the injury is minor and he should be ready in time for the trip to Miami in two weeks.

"Yeah, I think I could have (played, if needed)," Johnson said. "If I can walk, I can run, so that's just the mind-set I've always tried to play with. If I needed to, I think I could have."

So you were just being cautious?

"Yeah," he said. "I put my trust even more in my teammates. It's hard for me to do, being a competitor, but they got it done, I'm happy."