ROY KEANE'S early-season frustrations increased last night when he learned he will be without three members of his first choice midfield for at least a month.

With Sunderland captain Dean Whitehead ruled out for six months with knee ligament trouble, Keane had been hoping to hear that Carlos Edwards would have been available to face Reading in the Premier League tomorrow.

However, as well as Edwards' hamstring problem resurfacing, the Sunderland boss has also been informed that his third most expensive signing, Kieran Richardson, is now facing up to three months on the sidelines.

Richardson, the £5.5m purchase from Manchester United, has suffered a stress fracture to his back and could be out until Christmas.

Now Keane will have to shuffle his pack on a regular basis in an attempt to fill the holes vacated by the three players.

"We have had bad news on Kieran. He saw a specialist this week and he has a stress fracture of his back. We will have more news after he sees a surgeon," said Keane.

"I would have thought he will be out for two to three months. It's a major disappointment. Kieran was able to do elements of training but it affected him when he twisted or hit the ball hard.

"In the last week or two, we were hoping it might settle down, but clearly it's a lot more serious."

Richardson has not figured for Sunderland since having to withdraw early in the 2-0 defeat to Liverpool on August 25.

The 22-year-old had struggled to make an impact in his opening games under Keane and his unavailability over the course of the next few months is hardly going to help his confidence.

His absence means Sunderland are lacking options on the left flank again following the departure of Tobias Hysen to Gothenburg, although Ross Wallace does prefer to play further forward.

And the dearth of alternatives is replicated on the right, with Keane still struggling to find someone capable of filling in for Edwards.

Greg Halford, back from a one-game suspension, can play there, although he will have to improve his performance levels considerably after a dreadful start to life on Wearside.

Against Reading, Keane is more likely to play someone out of position again, with Anthony Stokes, Liam Miller and Grant Leadbitter all having played on the right in the past.

Edwards played an integral role in helping to bring Championship success to Sunderland last season but he pulled up with hamstring damage against Birmingham four days into the campaign.

It had looked as if Edwards would face Reading, only to break down again, and now he could face a further month on the treatment table.

"It's not the same injury but it's similar and in the same area," said Keane. "It's a setback for the lad and for us because he's a big player for us.

"It's the downside with hamstring injuries. We look at injuries, we look at players' recovery, but one thing we don't do is push them too much. It's just one of those things.

"He had a week's running with the medical staff and then he trained with us. He was doing OK and then he walked off saying he felt something. It's a blow."

Meanwhile, the heroes of Sunderland's 1973 FA Cup triumph will be at the Stadium of Light on Saturday to celebrate the memory of team-mate Ian Porterfield.

Flags were flying at half-mast at the Stadium of Light last night following Porterfield's death on Tuesday night at the age of 61, following a battle with cancer.

Nine members of the squad at Wembley that afternoon - Micky Horswill, Jim Montgomery, Bobby Kerr, Dick Malone, Ritchie Pitt, Ron Guthrie, Dennis Tueart, Billy Hughes and David Young - will join Sunderland's class of 2007 around the centre circle for a minute's applause before kick-off.

In addition, Brian Moore's commentary, as Porterfield smashed home the shot at Wembley which earned him legendary status on Wearside, will be played.