Kirby Lee-USA TODAY Sports

Out of the blue, Los Angeles Chargers showed up to the practice field Friday wearing a walking boot on his right leg and obviously was unfit to practice.

The last we saw from James was positive on Thursday, as he was making highlight-reel plays against the New Orleans Saints during joint practice.

It’s unknown how severe an injury James is dealing with at this time.

If the second-year star safety has to miss extensive time with a serious injury, then the Chargers’ secondary will certainly struggle to replace his production. Last year as a rookie, James racked up 105 tackles, three interceptions and 3.5 sacks, earning First-Team All-Pro honors and a trip to the Pro Bowl.