Matthews suffered the injury in the team's 34-3 season-ending loss to the Carolina Panthers. He played 61 offensive snaps in that game before exiting late in the fourth quarter.
Lisfranc injuries occur in the mid-foot. The recovery time varies, based on the severity of the injury -- sprain, dislocation, fracture or ligament rupture -- and if surgery is required. The most serious is a Lisfranc ligament rupture, which typically involves a fourth-month healing process. As one medical source explained, it's like an ACL tear to the knee, in regard to stability. The length of time for recovery isn't equal, of course.
The timing of the injury no doubt works in Matthews' favor as he'll have plenty of opportunity to recover before training camp. Since the Falcons will have a new head coach, they can begin offseason workouts on April 6, which could mean Matthews would likely miss the first part of those sessions.
Matthews, the sixth-overall pick of the 2014 NFL draft out of Texas A&M, started 15 games at left tackle after joining the Falcons as a right tackle. He suffered a high-ankle sprain in a season-opening win over the Saints and missed just one game due to the injury. Matthews' ankle eventually improved in the second half of the season, and he showed the ability to be an anchor for years to come.