Virginia Coach Mike London addressed Thursday the play in training camp thus far of defensive end Cam Johnson, who is expected to be one of the Virginia defense’s top players this season.

At ACC media days in July, London revealed that Johnson (Gonzaga) has sickle cell trait, which the coach believes may impact the player’s ability to maintain a high level of performance for extended periods of time. At Virginia’s media day earlier this month, Defensive Coordinator Jim Reid said he likely would limit Johnson to 45-50 snaps per game this season.

Last year, the Virginia defense was on the field for an average of 68.1 snaps per game during its eight conference contests. Johnson recorded a career-best 53 tackles and led the team in sacks (6.5) and tackles for a loss (14.5) in 2010.

Through the first six days of training camp, Johnson’s play has drawn rave reviews from the Virginia coaching staff, and London said in a teleconference Thursday he thinks Johnson’s elevated performance thus far is no coincidence.

“Different people use motivational aspects in different ways, and I think what has been talked about as far as (Johnson) not being able to go a certain number of plays, then maybe that’s something internally or externally that he’s using as a motivating factor,” London said. “The reality of it is that he can go as far as he can go as long as he can go, and some of the things we talked about prior to that down at ACC (media days) was about sometimes with the (sickle cell) trait, what you might be susceptible to.

“I think he’s kind of taken that and said, ‘You know what? I’m going to go as hard as I can go in as many plays as the coaches allow.’ ... Whether it’s Cam Johnson or anybody else, if they’re getting the job done by going as hard as they can, then they’ll play. But if not, then we’ve got to be smart and substitute at the appropriate times.”