Detroit Lions quarterback Hendon Hooker was still in concussion protocol, three days after he was injured in a preseason game against the New York Giants.

Lions coach Dan Campbell said Sunday that the team is looking into signing another player at the position so starter Jared Goff and potential backup Nate Sudfeld are not the only healthy quarterbacks for this week’s exhibition game at Kansas City.

Hooker was hurt in the third quarter on a run after leaving the pocket Friday night against the Giants, playing for the first time in 21 months since tearing a ligament in his left knee as a fifth-year senior for the Tennessee Volunteers.

He was 5 of 9 for 36 yards and had four carries for 34 yards, including a 16-yard run, in his professional debut.

Detroit drafted Hooker in the third round last year, knowing he would likely not play as a rookie and hoping he would at least develop into a dependable backup.

The defending NFC North champions gave Goff a $212 million, four-year extension in May and want to keep him upright for the regular season, which starts in less than a month, in their quest to reach the Super Bowl for the first time in franchise history.

The Lions will likely want to play Goff very little, if at all, on Saturday night in their second preseason game on the road against the Chiefs.

Detroit’s desire to add to its depth at quarterback may also address concerns with Sudfeld, who was 13 of 24 for 96 yards with an interception against the Giants.

The 30-year-old Sudfeld has played in six games since Washington drafted him out of Indiana in the sixth round in 2013.

A little more than a year ago, with a shaky situation at quarterback behind Goff, the Lions signed veteran Teddy Bridgewater and he retired after playing one season in Detroit.

If the Lions decide to sign a quarterback with starting experience, Ryan Tannehill was still a free agent on Sunday afternoon.

Tannehill was the Tennessee Titans’ No. 1 quarterback for eight games last season and has started 151 games, throwing 216 touchdowns, since Miami drafted the former Texas A&M star eighth overall in 2012.