Crewe Alexandra captain Perry Ng is set to sign for Cardiff City.
Railwaymen manager David Artell told BBC Radio Stoke that the 24-year-old right-back was on his way to Cardiff for a medical ahead of a deal which he says is "good for both clubs".
League One Crewe had earlier rejected a bid for Ng from the Championship side Artell labelled "disgusting".
The agreed fee for the Liverpool-born player will be an initial £350,000 which could rise to £500,000.
Ng is in the final season of his contract with Crewe, while Cardiff are eager to strengthen at right-back.
Jordi Osei-Tutu has been ruled out for a further four to six weeks with the hamstring injury the Arsenal loanee suffered in October.
Bluebirds boss Neil Harris has been forced to play midfielder Leandro Bacuna at right-back in recent months.
Cardiff have lacked depth in the position for a long time and, over the course of 2020, they saw four right-backs leave the club.
Lee Peltier joined West Bromwich Albion last January, Wales international Jazz Richards left in June after his contract expired, while Wales youth player Cameron Coxe also departed and Dion Sanderson has returned to Wolverhampton Wanderers following the end of his loan.
Cardiff have also had a bid accepted by Championship rivals AFC Bournemouth for defender Jack Simpson.
The offer for the Weymouth-born 24-year-old is reportedly £750,000 but the club are still to negotiate terms with the former England under-21 centre back.
Cardiff have lost five of their last six league games - also being knocked out of the FA Cup by Nottingham Forest - and host Queens Park Rangers on Wednesday night as they seek to climb the table from 15th.