The Jaguars signed QB Jordan Palmer after putting QB Blaine Gabbert on the IR. (US Presswire)

The Jaguars have placed QB Blaine Gabbert (arm) and WR Laurent Robinson (concussion) on the injured reserve, coach Mike Mularkey announced on Wednesday.

It's an especially surprising move for Gabbert, who earlier in the week was listed as questionable. Coach Mike Mularkey had named QB Chad Henne the starter, but Gabbert was believed to be available as a backup.

Henne completed 16 of 33 passes (48.4 percent) for 354 yards, four TDs and no INTs in a 43-37 overtime loss at Houston last week after coming into the game in relief of the injured Gabbert.

"He’s had some success at the position," Mularkey told the Florida Times-Union of Henne, a former starter for the Miami Dolphins. "Again, he was brought in here in case something happened to Blaine and to step in and produce, which he did [Sunday].He made some throws, and we made some things happen after the ball was caught, which we really haven’t had a lot of this year, and that’s what we need every week."

Robinson has dealt with lingering concussion symptoms all season after sustaining one in the preseason and two during the regular season. The prized free-agent acquisition has only 24 receptions for 252 yards and no TDs on the season.

The Jaguars have also signed QB Jordan Palmer, who was with the team in the preseason, to be Henne's backup. The Jags also added WR Carlton Mitchell, who last played for the Cleveland Browns in 2011 and has three career receptions for 31 yards.

Earlier this week, the Jaguars added WR Jordan Shipley, a third-year pro who was originally a third-round pick of the Cincinnati Bengals in 2010. Shipley has 56 career receptions for 614 yards and three TDs. He last played for the Tampa Bay Buccaneers and was waived on Sept. 25.

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