Free-agent quarterback Joe Callahan is expected to sign with the Baltimore Ravens, according to NFL Network's Mike Garafolo.

Callahan went undrafted out of tiny Wesley college, which participates in the NCAA's Division III, in 2016. He spent his rookie season on practice squads for the Green Bay Packers, New Orleans Saints, and Cleveland Browns. Callahan made his NFL debut the following season, appearing in Green Bay's regular-season finale after Aaron Rodgers was placed on injured reserve. He completed 5-of-7 passes for 11 yards in the Packers' 35-11 loss to the Detroit Lions.

Callhan hasn't appeared in an NFL game since. The 26-year-old was cut by the Philadelphia Eagles after training camp last year, and was waived by the Tampa Bay Buccaneers in April after signing a futures contract with the team in January.

Robert Griffin III, the Ravens' second-string quarterback, fractured his thumb during Saturday's practice. The team subsequently announced that he “will miss practice for at least a few weeks,” while ESPN's Adam Schefter reported that the veteran signal-caller could be out anywhere from four to eight weeks.

Griffin's injury presents a golden opportunity for rookie Trace McSorley, who had spent the early portion of training camp splitting time between focusing on special teams and being Baltimore's No. 3 quarterback. He now ascends to the Ravens' top backup, with Callahan next in the pecking order.

Lamar Jackson, the No. 32 overall pick of last year's draft, enters his sophomore season entrenched as Baltimore's starter. He threw for 1,201 yards, six touchdowns, and three interceptions as a rookie, also rushing for a whopping 695 yards, while leading the Ravens to a 6-1 record after taking over for Joe Flacco.