PRESTON boss Alan Irvine claims former Celtic youngster Ross Wallace is at the centre of a selection dilemma ahead of tonight's Coca-Cola Championship play-off semi-final first-leg clash with Sheffield United at Deepdale.

Wallace was sent off after removing his shirt - it was his second caution - after he curled in a superb free-kick winner for Preston in the 2-1 success at Birmingham two weeks ago.

That meant Wallace had to sit in the stands as Irvine's men ground out the 2-1 success over Queens Park Rangers that booked their place in the semis.

The Deepdale boss said: "It is the old dilemma of whether you change a winning team.

"Ross scored a superb winner for us at Birmingham in a game that was absolutely vital to helping us make the play-offs.

"With five goals this season from midfield, he has been a very important player for us at crucial times.

"But against QPR last weekend we got over the line with another good, solid performance which showed a lot of nerve.

"It will be a tough call over whether I bring Ross straight back in."

Irvine will benefit from the return to fitness of former Aberdeen defender Michael Hart, but former Scotland international Calum Davidson is out.

Irvine admitted the key to his side's successful bid for a place at Wembley will come down to striking the right balance against the Blades.

He said: "Whatever happens it will only be half-time and, as a result, it's vital we don't over-commit or are too cautious.

"It is very important you get the right balance in that respect, but also that we make the most of home advantage."

lWest Brom midfielder Graham Dorrans is set to sign a new contract - less than a year after making the switch from Livingston.

lTonight's Under-18 National Shield Final at Hampden between Bishopbriggs Academy and St Mungo's High, Falkirk, has been postponed due to a waterlogged pitch.

The match will go ahead on June 2 or 5.