Leeds skipper Jonny Howson is hoping to learn the full extent of his knee injury after consulting a specialist on Friday.Midfielder Howson, 23, sustained the injury during last weekend's home win over Millwall and looks set to miss this Saturday's clash at Watford.Manager Simon Grayson said: "Jonny will be seeing a specialist on Friday morning. We've been looking at every angle this week and have been assessing him and the severity of it."Sometimes these things can look worse than what they are. We should know more after the weekend."Howson has not missed a game through injury since Leeds returned to the Championship in 2010 and started in all 46 league games last season.