Afterward, Bosa hobbled off the field on his own and spent the rest of practice receiving treatment from the team's training staff.
Bosa is "fine," and the injury is "nothing serious," a source with knowledge told ESPN's Adam Schefter.
The No. 3 overall selection of the 2016 draft, Bosa led the Chargers in sacks last season with 12.5, and he is one-half of the Chargers' talented pass-rush tandem that includes Melvin Ingram, who finished with 10.5 sacks last year.
Bosa played a full, 16-game season for the first time in his NFL career in 2017, earning a trip to the Pro Bowl. The Ohio State product missed the first four games of his rookie season with a hamstring issue after sitting out of training camp because of a contract dispute.
The Chargers already lost two of their front-line players for the season to injury, with tight end Hunter Henry suffering a right ACL knee injury in May and cornerback Jason Verrett suffering an Achilles tear during a conditioning test before the start of training camp.