ROBERT Koren faces a race against time to be fit for Saturday's trip to Barnsley (ko 3pm).

The Baggies midfielder has started the last 17 Championship games but picked up a calf problem in the 2-1 win over Burnley at the weekend.

And Tony Mowbray has revealed the 27-year-old ace will not return to training until the end of the week at the earliest.

"Robert picked up a calf injury against Burnley," said the Baggies boss.

"He hasn't trained today and we probably won't try him in training until the end of the week.

"I'd say his chances of playing against Barnsley are only 50/50 at the moment."