Roma midfielder Kevin Strootman is expected to be on the sidelines for "much longer" than first thought after he picked up an injury playing against Fiorentina last weekend.
The 24-year-old spent a large part of last year on the treatment table after suffering ligament damage back in March.
The Netherlands international returned to action last November and has featured in all four matches of 2015, but following surgery on a knee injury that he picked up in Sunday's 1-1 draw, he will be out of the first team for some time.
Strootman wrote on Twitter: "The scar tissue from my previous operation has been removed successfully today. Unfortunately some cartilaginous damage, caused by the knock in the Fiorentina match, was found too.
"This means I have to take a longer rest period than anticipated earlier and I am extremely disappointed that it will take much longer before I can be back on the pitch again."
Strootman has been linked with a move to Manchester United for some time.