Everton defender Tony Hibbert has undergone surgery after failing to recover fully from a knee problem.
The 27-year-old suffered ruptured ligaments against Arsenal on May 4 and Everton had hoped putting the knee in a brace would solve the problem, however he remained uncomfortable when running.
Hibbert may now miss the start of the season, but Everton are hopeful he will be available to manager David Moyes for the league opener against Blackburn on August 16.
Club physio Mick Rathbone told evertonTV: 'We put it in a brace for six weeks, because surgery is to be avoided at all costs.
'We have got him running flat out in a straight line, but any side-to-side stuff and he just doesn't feel right.
'Hopefully he will be there or thereabouts for the start of the season. It's touch and go.'