Wales number eight Taulupe Faletau is in talks to leave Bath at the end of the season and join Cardiff.
The 30-year-old British and Irish Lions back row joined Bath from Dragons in 2016.
No deal has officially been completed but Faletau is expected to play at the Arms Park from next season.
Faletau has not played so far this season because of an ankle injury and missed Wales' 54-16 defeat against New Zealand.
He was unavailable for the All Blacks game with English clubs not releasing Welsh players because the Test match was organised outside World Rugby's international window.
A move back to Wales would avoid a similar scenario from happening next season.
Cardiff have already confirmed Wales flanker Thomas Young will join the region from Wasps for the 2022-23 season where he will link up again with director of rugby and father Dai.