Scottish Premiership leaders Hearts will be without key defender Stuart Findlay for six weeks while record signing Eduardo Ageu will miss the rest of the season.
Head coach Derek McInnes also confirmed goalkeeper Craig Gordon's shoulder injury could keep him out of Scotland's March friendlies against Japan and Ivory Coast.
Findlay, 30, has been a pivotal figure for the league leaders having started all 28 Premiership matches in the middle of defence, but was forced off in the win over Falkirk with a hamstring injury.
Brazilian midfielder Ageu made the first start of an injury-hit debut season against Rangers at Ibrox, but was taken off and will now be sidelined until next season because he needs thigh surgery.
Gordon has also played limited minutes for Hearts this term, but is one of Scotland's key players as they prepare for a first World Cup finals since 1998.
Beni Baningime, Oisin McEntee and Sabah Kerjota also have knocks but still have a chance of playing against Aberdeen on Saturday.
McInnes says he hopes Findlay and captain Lawrence Shankland, who has been missing since 17 January with a hamstring injury, will be back for the final pre-split game against Motherwell on 11 April.
Hearts are four points clear of Rangers at the top of the Premiership.
More to follow.
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