He was stretchered from the pitch at the Memorial Stadium, and a series of X-rays last night have revealed the 28-year-old fractured the tibia and fibula in his right leg.

A statement on club website www.whufc.com said: "It is too early to say at this stage how long the player will be out for as this will become clearer once the first stage of surgery is completed."

After last night's game, Hammers manager Alan Curbishley revealed his anger at Jacobson's 10th-minute tackle on Dyer, which led to furious exchanges between the opposing players.

"I just can't put it into words," he said.

"The game was just immaterial after that and I think that the Bristol Rovers' player has got to be very disappointed with his tackle because, as far as I could see, he lashed out after losing the ball.

"The players could see what he did and that's why they were so angry."

But Rovers manager Paul Trollope defended Jacobson, insisting: "Joe is an honest lad and he swung his leg to get the ball. It was just an unfortunate incident."

The injury is the latest serious fitness problem suffered by the former Newcastle midfielder, who made his international debut against Luxembourg in September 1999.

Previous setbacks include a stress fracture of the foot, knee ligament trouble, shin splints and injuries to his back and hamstring.

The new injury is sure to rule Dyer out of the remainder of England's European Championship qualifying campaign which ends in November, and he may even struggle to prove his fitness in time should Steve McClaren's men qualify for next summer's finals.