Danny Fox will have a medical at Wigan on Tuesday ahead of a permanent move from Nottingham Forest.
Wigan had seen an offer for the 32-year-old defender rejected by Forest earlier in January but are set to complete the deal after Martin O'Neill left him out of the squad that beat the Latics 3-1 on Saturday.
Forest were keen to keep Fox, who had been team captain for most of this season, although his contract would be expiring in the summer.
Fox originally joined Forest from Southampton in January 2014 on a loan deal made permanent in the summer, and went on to make 123 appearances during his five-year stint at the City Ground.
Forest are looking to add a defender to their squad before the end of the January transfer window as they are in talks to sign young West Ham defender Reece Oxford.
The club announced on Monday that Roy Keane will be reuniting with O'Neill as his assistant manager at the City Ground after their experience together in the Republic of Ireland national team.