Ron Vlaar has confirmed that he will spend the next four months on the sidelines with a knee problem.

The centre-back, who is a free agent following his recent release by Aston Villa, has been forced to undergo surgery on a torn medial ligament.

"Instead of two days with crutches, there will now be a four to six-week period. Instead of four weeks' rehabilitation, it will now take three to four months," the 30-year-old wrote on his blog.

"Two days after surgery the knee is very stable and that is the basis from which to start exercising."

The Netherlands international has been linked with moves to Southampton and Lazio.