Middlesbrough defender Matthew Bates has undergone a fifth cruciate knee ligament operation, leaving his future in doubt.
The 25-year-old has been troubled by injury in recent seasons, but Middlesbrough boss Tony Mowbray has vowed to back the defender.
"It's obviously a bad injury. We wish him well in that quest, that battle to get himself fit again. But the club will support him in every way that we can and we wish him well," Mowbray told reporters.
Bates has been at the club since 1998.