Burrow was forced off just three minutes into the fourth-round tie at Headingley after a challenge from Wildcats loose forward Paul Aiton and will undergo x-rays on Saturday to determine the exact damage.

"We don't think he's broken it but everything swelled up like he has broken it," said Rhinos coach Brian McDermott. "The little fella is in pain and he's in for a rough night's sleep."

Forced to re-shuffle his side, McDermott admitted it took some time for his side to find their rhythm.

"I was massively worried," added McDermott. "We've got some very used bodies out there that have done a lot of game time.

"When we lost Rob, we had to put other people into different positions and have a bit of a makeshift attack in the first half.

"I have to give the players a lot of credit for turning things around. It was a huge effort in the second half."

Leeds had skipper Kevin Sinfield placed on report after a skirmish towards the end of the first half and McDermott believes he was frustrated by the poor standard of refereeing.

"That game was refereed to the lowest common denominator," he said. "I don't know what dominant play is based on that game tonight.

"I'm not having a go at Richard Agar, who is doing a fantastic job at Wakefield, or Richard Silverwood because he is refereeing to instructions, but when you can get away with not being square, or slightly offside or piling in or shutting play down, some players and coaches will go for it.

Frustrating

"I'm talking about rugby league in general and it frustrates me. I just thought it was a terrible game of rugby league. There were some fantastic tries but there was no momentum and it was scrappy."

Wakefield coach Richard Agar was critical of his players for letting slip a winning position with some sloppy defence in the second half.

"In the first half I thought we were excellent and a bit unlucky not to come in with a few more points on the board and a better lead," he said.

"We put ourselves in with a chance and overall I'm pretty disappointed with the second half. We knew Leeds would up the tempo and we needed to go with them.

"Leeds were a bit off in the first half and, with the amount of line breaks, we should have had more points."