Daryl Horgan has proved to be a real success since arriving at Deepdale from the League of Ireland

Having already done a deal for team-mate Sean Maguire, the Lilywhites are set to make it a double deal with the former Republic of Ireland Under-21s international full-back also Deepdale bound.

Sources in Ireland say a deal between the two clubs is done, with the 22-year-old on the verge of signing.

Like Maguire, who has scored 19 goals in 20 games so far this season, O’Connor is a key part of the Cork side that sits 18 points clear at the top of the table.

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An attack-minded full-back, he can play in a back four, in front of a conventional left back or as a wing back.

O’Connor is also known for his excellent set-piece delivery. A good friend of Maguire’s and PNE midfielder Alan Browne – a former Cork City man himself – his arrival would see North End sign another League of Ireland pair.

Daryl Horgan and Andy Boyle are already firm fan favourites after their moves from Dundalk in January.

O’Connor would also create further competition down the left.

Greg Cunningham is expected to return in time for pre-season from his fractured tibia, while Tommy Spurr will be entering his second season at Deepdale.

Defensive reinforcements are needed though, with captain Tom Clarke set to be out until well into 2018 with his ruptured Achilles tendon.

PNE will be looking to build on their 11th place in the Championship last season without their captain.

And the Lilywhites’ success has not gone unnoticed, manager Simon Grayson being strongly linked with the vacant managerial post at Sunderland yesterday. Odds tumbled on the Lilywhites boss moving to the North East but the Post understands the Mackems have not made any contact in a bid to secure Grayson’s services.

The North End boss has already been linked with the managerial vacancies at Hull, Middlesbrough and Leeds this summer, with plenty of sides on the lookout for a new boss.

A successful four years at Deepdale, Grayson having taken over with Preston 17th in League One, have certainly caught the eye.

Sunderland remain on the lookout for someone to replace former Lilywhites boss David Moyes following his resignation after their relegation from the Premier League.