Leeds United defender Stuart Dallas suffered a broken leg in his team's 4-0 defeat by Manchester City at Elland Road on Saturday, the club said in a statement.
Dallas was injured while making a challenge on City's Jack Grealish in first-half stoppage time and received medical attention on the pitch before being carried off on a stretcher.
"Stuart Dallas faces a lengthy period out of action due to a femoral fracture sustained in yesterday's Premier League game with Manchester City," Leeds said on Sunday.
"Stuart was kept overnight at Leeds General Infirmary and will now travel to London for surgery and further tests."
Leeds are 17th in the table, five points above the relegation zone and next play Arsenal on May 8.
