Middlesbrough defender Seb Hines could miss the start of next season after being told he needs knee surgery.
The 24-year-old defender is to undergo surgery to repair a micro-fracture, and that could sideline him for up to four months.
Manager Tony Mowbray told the club's official website: "Potentially he could be out for four months, and we wish him a speedy recovery.
"He's a strong lad with a good mentality, so he will come through it fine. He's a warrior for us and has played through discomfort at times."
With Jonathan Woodgate suspended following his dismissal at Bolton last weekend, Mowbray has only three fit central defenders available for the npower Championship clash with Charlton as Andre Bikey, Rhys Williams and Stephen McManus compete for the starting berths.