Hearts are facing up to two months without captain Lawrence Shankland as the Scotland striker recovers from a hamstring strain, while the Scottish Premiership leaders have agreed a deal to speed up the signature of Rogers Mato.
The Uganda international, 22, had agreed to join under freedom of contract in the summer, but now a fee has been settled with FK Vardar in North Macedonia.
With work permit and visa issues pending, Mato is unlikely to join in time for Sunday’s home game against champions Celtic.
Shankland, 30, scored his 15th goal of the season in Saturday’s Scottish Cup loss to Falkirk before going off in extra-time.
A brief statement via social media revealed Shankland “will miss the next six to eight weeks”.
Hearts recently lost influential midfielder Cammy Devlin for a similar time scale due to a leg injury, while Oisin McEntee, Stephen Kingsley and record signing Eduardo Ageu are also sidelined for the Edinburgh side and Beni Baningime is suspended for the weekend’s big game.
Shankland, in his fourth season at Tynecastle, will be absent for the next derby at home to Hibernian on 10 February, which is followed by a trip to face Rangers at Ibrox.
Hearts are six points in front of Celtic and Rangers with 16 league matches remaining.
With 11 goals, Shankland is the Premiership’s top scorer, while team-mate Claudio Braga has nine.
Central defenders Craig Halkett and Stuart Findlay are the next best with four goals each.
Pierre Landry Kabore and Elton Kabangu came off the bench for Hearts on Saturday, with teenager James Wilson another option in attack.