Redknapp wrote in The Sun: "England striker Rooney's problems with the club come from a different direction.
"Maybe things have gone too far there now, maybe it is the case that he will be leaving.
"There may be that there is no way back for Rooney and the club now.
"This could well explain why United are making such a big play for Fabregas.
"They are desperately short in that area of the pitch - and losing Rooney would leave a big hole for United to fill.
"Fabregas is a big name - and he could fill it."