Southampton are pushing through a £7million deal for Mislav Orsic from Dinamo Zagreb.
The deal hit a snag this week over the fee but the Premier League strugglers increased their offer and the Croatia international, 30, began his medical on Thursday.
Nathan Jones' side are bottom of the Premier League with just one win in their last 13 top flight games and are in need of arrivals to boost their survival bid.
Orsic has scored 13 goals and provided eight assists across 27 appearances in all competitions this season.