RYAN JACK is out of Scotland's World Cup play-off semi-final against Ukraine after picking up a calf injury, with Luton Town's Allan Campbell called up in his place.

It is the latest fitness blow for Rangers midfielder Jack, who also missed the European Championships last summer and spent a large part of the domestic season on the sidelines with a calf issue, before missing further action through an ankle problem recently.

His absence though has left the door open for Campbell to win his first call-up to the senior Scotland squad, after the former Motherwell man enjoyed an impressive debut campaign in the English Championship.

Campbell, 23, is a former captain of the Scotland under-21 side, picking up 24 caps at that level to leave him third on the all-time list.

He has previously spoken of his hopes that a move to England would improve his chances of a call-up to the senior squad, and Jack's injury has handed him that opportunity.

“I got a taste of the 21s and once you get over that age then you strive to get into the men’s squad," Campbell said.

"Seeing the Scotland fans and the buzz about the Euros, you have a real bit [of fire] in your belly to try and be there, and hopefully I can come here, perform well and try and get in the manager’s eye.”