Tottenham midfielder James Maddison is expected to miss the final three weeks of the season with a knee injury.
The 28-year-old scored but was then injured during last Thursday's 3-1 win over Bodo/Glimt in the Europa League semi-final first-leg.
Head coach Ange Postecoglou sounded positive in the immediate aftermath of the game.
But it became clear on Friday morning that the injury was more serious than first feared and subsequent scans have confirmed that.
Sources have indicated that Maddison is being assessed for knee ligament damage, the extent of which will be clarified in the next 48 hours.