Los Angeles Rams quarterback Matthew Stafford experienced hamstring tightness and did not finish Wednesday’s joint practice against the Dallas Cowboys, a team official told reporters.

Rams quarterbacks Jimmy Garoppolo and Stetson Bennett took over reps as Stafford watched from the sideline.

Garoppolo, who signed with Los Angeles in March to back up Stafford, is suspended for the first two games of the season for violating the NFL’s performance-enhancing substances policy.

Stafford was scheduled to speak to reporters after practice but that news conference was canceled. Rams coach Sean McVay was not scheduled to talk to reporters Wednesday.

In 15 games last season, Stafford completed 62.6% of his passes for 3,965 yards with 24 touchdowns and 11 interceptions.