Rex Ryan 'very concerned' about Ragland's knee injury

Buffalo Bills second-round rookie Reggie Ragland left Friday's training camp practice after suffering a knee injury.

Head coach Rex Ryan later told reporters that while the ailment doesn't appear to involve any ligaments, he is "very concerned" about the young linebacker.

A more solid update on Ragland's status should be available after the training staff has the opportunity to run more tests. For the time being, though, the Bills are left to contemplate the possibility of a second premium draft pick being forced to the sidelines.

First-round defensive end Shaq Lawson will start the season on the physically unable to perform list after undergoing shoulder surgery during the offseason. Timelines for his expected return have varied, but it appears certain that he'll miss at least the first month of his rookie season.

Both Ragland and Lawson can be expected to take on starting roles when healthy. Extended absences for both would be a tough break for a Buffalo defense looking to bounce back from a disappointing 2015 campaign.