Leeds winger Luis Sinisterra is expected to be ruled out until after the World Cup winter break due to a rare foot injury.
The 23-year-old Colombia international, who signed from Feyenoord in the summer for a reported £21million, damaged ligaments in the recent home defeat to Fulham.
He missed last Saturday’s Premier League win at Liverpool and will sit out Saturday’s home game against Bournemouth.
Leeds head coach Jesse Marsch said: “Luis Sinisterra has a foot injury that turns out to be more than what we originally thought it was.
“He wasn’t making the progress that we were hoping he could make over the last 10 days, so they did another scan and they had a specialist look at it and they started to worry about it being a Lisfranc injury.
“It’s a rare injury. It (the Lisfranc ligament) controls the movement of the metatarsals and when that is ruptured, it can be a long recovery.
“We don’t believe it’s ruptured, we believe it’s partially torn, which puts him in a little bit of a grey area, but probably out until after the World Cup break.”
Sinisterra has proved a big hit since arriving at Elland Road, scoring three goals to help ease the disappointment of former fans’ favourite Raphinha’s summer departure to Barcelona.
Leeds’ shock win at Anfield last Saturday snapped an eight-game winless league run and lifted the pressure slightly on Marsch.
A section of Whites fans had called for the former Salzburg and Leipzig boss to be sacked after his side slipped into the bottom three.
They now sit 15th, one point clear of the relegation zone, but Marsch knows victory against Bournemouth is crucial if his side is to maintain progress.
“Obviously it was a good win, but it’s kind of frustrating that we can perform like this in certain games and then we’ve let two many points slip away in others,” he added.
“We should be further up the table, further along in our process, but we’re not.
“There’s joy that we get a result like that, but also concern and frustration that we haven’t done more in other moments.
“This week there’s been real concentration on what’s necessary this weekend and our focus entirely is to build momentum.
“To do that we have to get a result and a win against Bournemouth.”
Marsch has no new injury worries, while teenage midfielder Archie Gray (toe) has returned to training. Stuart Dallas (fractured femur) and Adam Forshaw (ankle) are still out.