Middlesbrough have confirmed that Justin Hoyte will be sidelined for six weeks.
The full-back pulled a hamstring during Boro's 3-1 win over Reading at The Riverside at the weekend.
Hoyte has only just won his place back in the Boro first team but now he will be out until November.
"It's disappointing for Justin. He put in two excellent performances for us last week," said Boro boss Gordon Strachan.
"It looks a bad one. So we're talking about six weeks."
Matthew Bates, who was rested against Reading, now looks set to come in for Hoyte at Watford this Saturday.
"We said at the start of the season that we would be bringing Matthew along at a sensible rate," said Strachan.
"After what he has been through it was important that we approached it the right way and gave him every chance to establish himself again.
"Our medical man Grant Downie said that we shouldn't be giving him too much football. That's why we left him out at Chesterfield and at Millwall.
"His career is far more important than individual games."