SIMON GRAYSON is confident James Vaughan will hit the goal trail soon – but has warned the rest of his Sunderland squad they cannot rely on the striker to plug the gap left by hamstring victim Lewis Grabban.

Grabban faces around a month on the sidelines after damaging his hamstring in the first half of Tuesday’s 1-0 defeat to Nottingham Forest, and his absence means Vaughan is set to lead the line in this afternoon’s game at Hull City.

The former Everton forward is still to score his first Black Cats goal after making a £500,000 summer move from Bury, and while he has been a willing enough worker in the first six weeks of the season, he has rarely looked like posing a threat in front of goal.

Grayson is confident that will change, but with only four players having found the target in the league this season, the Sunderland boss also accepts it is vital his squad start coming up with goals from other areas.

“It’s a confidence thing, and strikers go through these spells where they don’t score goals,” said Grayson. “It can drag on a bit, but then before you know it they get a couple of goals and hit a rich vein of form.

“Vaughan works extremely hard for the team, and somewhere down the line he’ll get a goal and hopefully that’ll be something that kick-starts him, but other people have to join in too. When we get into key areas, it can’t just be about the strikers.”

The scan results on Grabban’s injury were due yesterday, but while Grayson was reluctant to be too specific on the length of his anticipated lay-off, the Bournemouth loanee will not be a short-term absentee.

“Anybody who comes off with a hamstring will be out for a period of time,” said the Black Cats boss. “It’s very rare that a player will come off like that and only be out for a week or so.

“You might be talking a few weeks, but I don't know because I've not had the scan results yet. Let's hope it isn't too severe, but it's something that's probably not going to be just a few days, that's for sure.”

John O’Shea will also miss today’s game with a calf problem sustained in the defeat to Sheffield United, but Aiden McGeady and Lamine Kone could return to the squad after training yesterday.

“We're waiting on McGeady and Kone to see how they are,” said Grayson. “They hadn’t trained with us (before yesterday), but they’ve been out doing work with the physios.”

Duncan Watmore has also been training this week, and is due to make a 45-minute appearance in today’s Under-23s game with Manchester City.

“He's had a good week's training,” said Grayson. “That's a big boost for Duncan and ultimately us as a football club. Let's hope he comes through nicely and then we'll progress from there, but we're certainly not in a position where we're going to throw him back into the first team on Wednesday at Everton because he's been out for such a long time and we have to be very careful with that.”