WIGAN, England, May 14 - Wigan Athletic chairman Dave Whelan said on Monday he believes West Ham could still be relegated if Sheffield United can prove the London side registered Carlos Tevez illegally for a second time.

He was speaking in the aftermath of West Ham securing Premier League survival with a 1-0 win at champions Manchester United on Sunday.

That came just over two weeks after West Ham were fined, not deducted points, for breaching ownership rules over Argentine signings Tevez and Javier Mascherano.

Sheffield United's 2-1 home defeat by Wigan on the last day of the season meant they dropped out of the Premier League on goal difference while Wigan survived.

Whelan accepts there is no chance of overturning the Premier League's decision to fine West Ham 5.5 million pounds ($10.9 million) instead of deducting points last month when the club admitted the player's initial registration was illegal.

But he is adamant the second registration was also illegal -- an assertion denied on Monday by the Premier League -- and wants West Ham to face another disciplinary committee. He said Wigan and three other clubs were backing action.

"We can't reverse the earlier decision, we have to accept that, but if he has been signed illegally again, then West Ham will go down," Whelan told reporters on Monday.

"I feel he has been registered illegally for a second time. How can they open a new transfer window to sign the player?

NEW WINDOW

"They opened a new window at 4pm on Friday and left it open until midday the next day so he could play against Wigan."

When the two sides met the following day, West Ham won the match 3-0.

Whelan said on Monday that Sheffield United were waiting on a circular from the Premier League before deciding what legal action to take.

"I spoke to the chairman of Sheffield United (Kevin McCabe) this morning and told him to get stuck into the Premier League because we are right behind you."

The Premier League denied on Monday that West Ham had re-registered Tevez. "There was no second registration, there was no re-opening of the transfer window," a Premier League spokesman told Reuters.

"The only thing that was decided on April 27 was the status of (West Ham's) third party agreement."

He said the Premier League would write to all 20 clubs on Tuesday to clarify the situation.

Asked earlier in the day by BBC Radio about wider support, McCabe said: "It will need conversations with chairmen and directors so they understand all of the injustices, so I suspect we will be canvassing."

The BBC reported that two other unnamed clubs had pledged support to the challenge.

But Middlesbrough later distanced themselves from legal action, although the club's chief executive Keith Lamb said they wanted clarity on the situation.

"We have raised concerns with the Premier League about the process that led to Carlos Tevez being allowed to play in West Ham's most recent games," he told the club's Web site.

West Ham were punished because the original contracts of Tevez and Mascherano gave certain rights to third-party companies. After the panel's verdict, changes were made that enabled Tevez to keep playing.

The Argentine forward proved key to West Ham's late revival, in which they won seven of their last nine league games, notably scoring Sunday's winner at Old Trafford.