Emerton, who returned to action earlier this season after a long-term knee injury, had to be replaced on 23 minutes at St Andrews in Tuesday's Premier League match.

The injury comes just days after club and country teammate Grella injured his groin against Hull City.

Elsewhere overnight, Neil Kilkenny scored a goal to help Leeds United overcome Dean Bouzanis' Accrington 2-0 to qualify for the final four of the Johnstone's Paint Trophy.

Hogan Ephraim opened the scoring for the Whites early, before Kilkenny headed a 50th minute cross past Bouzanis.

The header made it four goals in nine games for the Aussie midfielder who has been in a rich vein of form lately.

Kilkenny played the full match along with Bouzanis, who made some good saves, while Patrick Kisnorbo, who recently returned from injury, was a 77th minute substitute.

Finally overnight, Simon Storey and Frankie Lagana both played full games as Airdrie United drew 1-1 with Raith Rovers in Scotland's Division One.