RB Toby Gerhart (hip) out Friday

JACKSONVILLE, Fla. -- Running back Toby Gerhart will miss the Jaguars' preseason opener on Friday because of a lingering hip flexor injury.

Gerhart has missed the last five practices, including last Saturday's scrimmage, and coach Gus Bradley said the team is being cautious with the player they signed in March to be their feature back this season.

"He's made great progress but we just felt like at this point in time, for the number of carries he's going to get in there, we'd rather have that recovery time," Bradley said.

Gerhart signed a three-year, $10.5 million contract with the Jaguars after spending the first four years of his career backing up Adrian Peterson in Minnesota.

The Jaguars will also be down another receiver for Friday's game against Tampa Bay at EverBank Field. Mike Brown, whom receivers coach Jerry Sullivan called the team's best receiver in camp, suffered tightness in his hamstring during Wednesday's practice and is listed as day-to-day.

"It was just something that was kind of precautionary," Brown said of being pulled from practice. "We'll see how it goes. Go in and get treatment and try to get ready for tomorrow."

Brown is the sixth Jaguars receiver to go down with an injury. Cecil Shorts (hamstring), Allen Robinson (hamstring) and Tandon Doss (ankle) are out. Damian Copeland (wrist) was placed on IR on Monday and the Jaguars waived Nathan Slaughter (wrist) Wednesday with an injured reserve designation. In addition, Ace Sanders has taken a leave of absence in advance of a four-game suspension for violating the NFL's substance-abuse policy.

The Jaguars signed former New York Giants third-round draft pick Ramses Barden, who has 29 catches in 29 career games, and Chad Hall, who has played in 24 games with Philadelphia and Kansas City. He has 16 career catches and also has returned punts and kickoffs.

Only one of the Jaguars' six other receivers has played in more than two NFL games. Kenny Shaw, Marqise Lee and Allen Hurns are rookies. Chad Bumphis is a first-year player who has spent time on the practice squad with three teams. Lamar Thomas has two career catches in two games and Kerry Taylor has 22 catches in 10 career games, including 19 with the Jaguars last season.