CELTIC defender Gary Caldwell has warned his team-mates they face one of their biggest tests of the season when they travel to Hearts on Sunday.

Gordon Strachan’s men have won five league matches in a row since losing the Old Firm derby at the end of August, but Caldwell will take nothing for granted at Tynecastle.

“It is one of the biggest challenges in the season and we need to go there and keep the run going,” he said.

“It is always a great game, a good atmosphere and we will have to recover and be ready for it.”

That recovery period will be only three days following Wednesday night’s CIS Cup victory at Kilmarnock.

A four-day break is the most the Hoops can expect in the next fortnight, with games against Manchester United, Motherwell, Kilmarnock and Hamilton all on the horizon.

Strachan will be hoping this is where his controversial rotation policy comes to the fore, especially with the injuries starting to mount at Parkhead.

Skipper Stephen McManus has been added to the squad after recovering from a tight hamstring.

Midfielder Shunsuke Nakamura, who was substituted in Wednesday’s CIS Cup quarter-final win at Kilmarnock with a thigh injury, is also fit again.

Defender Glenn Loovens missed the trip to Ayrshire with a thigh injury picked up against Hibernian last week and joins Jan Vennegoor of Hesselink, Chris Killen, Georgios Samaras and Marc Crosas on the sidelines.

Provisional squad: Boruc, Hinkel, McManus, Naylor, Wilson, O’Dea, Caldwell, Scott Brown, Donati, Nakamura, Hartley, McGeady, McDonald, Sheridan, Maloney, Mark Brown, Robson, McCourt and Caddis.