Cahill injured his calf in the second-half of the 2-1 win over the Portuguese club at Goodison Park and had to be replaced on 62 minutes.

The injury came after the Australian international had brilliantly set up Steven Pienaar for the opener with a wonderful backheel.

Sylvain Distin doubled Everton's lead early in the second-half, before Sporting grabbed a handy away goal from the spot via Miguel Veloso.

After the game Everton boss David Moyes admitted he was unsure about the extent of Cahill's injury.

"Cahill may have a calf strain, we're not sure of the severity yet," Moyes said.

Elsewhere on Tuesday night, Scott McDonald missed a late penalty, and the chance to get off the mark at his new club, as Middlesbrough were defeated 2-0 by Blackpool.

Despite his penalty miss McDonald was one of Boro's better players causing Blackpool plenty of problems, while fellow Aussies Brad Jones and Rhys Williams were not involved.

In League One, Patrick Kisnorbo remains on the sidelines with an Achilles injury as Leeds United lost 2-1 to Walsall.

Neil Kilkenny and Shane Lowry both started for the Whites, with the former replaced on 75 minutes.

Elsewhere in the English third tier, Dean Heffernan put in a full shift, picking up a yellow card as Huddersfield won 2-1 at Carlisle.

In League Two, young goalkeeper Dean Bouzanis was dropped to the bench as Accrington lost 2-1 at Chris Herd's Lincoln City, while Oliver Bozanis started and played just over an hour as Aldershot lost 2-0 at Hereford.