The Premier League champions have already rejected two bids from Chelsea, the second of which was worth £30 million, with Jose Mourinho keen to add the 27-year-old to his squad before the transfer window shuts.
Wilkins represented both clubs during his playing career but thinks Rooney would be making a mistake if he moves to Stamford Bridge and believes he should battle to establish himself under new Red Devils boss David Moyes.
|16/1||Wayne Rooney is 16/1 with Paddy Power to be the Premier League's top scorer
“Man United are in the top three biggest clubs on the planet, therefore they will always buy and buy and buy because they always want to be successful.
“If you want to win things then there’s no better club to be at than Manchester United.
“So what if you’ve got a bit of competition with Robin van Persie, it’s healthy. He should stand up to the plate and show these people what he's made of. He’s got so much wonderful football left in him."
Wilkins thinks Moyes should only consider selling Rooney if a foreign club makes an offer, although he has conceded he would love to see him play for Chelsea.
“If I was David Moyes there’s no way I would sell him to anyone in England,” he added. “I’m sorry – he’d have to go abroad.
“I would love him to join Chelsea though. I would love nothing more than to see Wayne Rooney wearing that blue shirt.
“I just think he’s ready for his second coming, he’s 27-years-old and if for some strange outcome he stays in England, then Wayne is ready to start again.
“Man United would be crazy to do that though, they shouldn’t sell him to one of their closest rivals.”