GROUP B: Paul Hartley and Gary Caldwell have been ruled out of Scotland's crucial qualifier against Ukraine at Hampden on Saturday.

Celtic midfielder Hartley pulled up during Celtic's 2-1 win over Gretna, while defender Caldwell sustained a knee injury in the same game.

Caldwell may recover to face Georgia next Wednesday, but Hartley will be out for up to three weeks.

Scotland manager Alex McLeish said he had yet to decide whether to add anyone to his 22-man squad.

The loss of both players could force McLeish to alter his plans for Saturday's visit by Ukraine.

"We'll need to sit down and look at things carefully before making any decisions," said.

"Of course I'd have preferred Paul and Gary to be fully fit but I won't rush into any decisions. I'll have a good look and see what action to take, if any. These things happen and a manager can't sit back and fret."

Hartley played a key role in a defensive midfield guise for Scotland in the victory over France in Paris last month.

McLeish's midfield options are becoming limited with Manchester United's Darren Fletcher also out due to injury and suspension.

The loss of Caldwell means Scotland will have reduced cover in defence.