Doyle has found himself out of favour at Cardiff this season, with his only appearances coming in the Capital One Cup.
The Irishman joined Cardiff from Chesterfield last January after scoring 25 goals in League One over the first half of last season, but he has struggled to make an impact at the Cardiff City Stadium.
Cardiff boss Russell Slade is happy to loan out Doyle as he does not figure in his current plans, with Kenwyne Jones and Joe Mason ahead of him in the pecking order.
A number of clubs have expressed an interest in Doyle, but Preston are at the front of the queue to sign the 27-year-old.
Preston boss Simon Grayson is desperate to bring in a new striker before the close of the transfer window, with Jermaine Beckford facing a spell on the sidelines through injury.