Ivan Cleary has applauded James Tamou's leadership development as the Penrith skipper looks set to join Wests Tigers on a two-year-deal next season.
Salary cap limitations have forced Tamou to look elsewhere to extend his NRL career in 2021 and his appointment at the Tigers is likely to be formally announced next week.
The former NSW and Australia prop will turn 32 at the end of the year and his leadership will be crucial for Michael Maguire's side after helping steer the Panthers to the top of the ladder.
It's understood the Panthers initially offered him a one-year deal to stay next season, but the club could not match more lucrative deals put to him by NRL rivals.
"I've been talking to Jimmy right through the process really, just staying updated. It's a really difficult situation for us," Cleary said on Thursday.
"Jimmy has been an integral member of our side and obviously our captain.
"The way he's grown as a leader in the last season and a half has been amazing and special to watch.
"He has such an influence on our young team, his performances have been consistent week in and week out.
"If he ends up going to another organisation they're going to get a good one that's for sure."
It is set to be a blow for St George Illawarra after incoming coach Anthony Griffin targeted Tamou to join the Dragons' pack next season.
The addition of Tamou will plug a leadership gap for the Tigers side who will lose Benji Marshall, Chris Lawrence and Elijah Taylor next season as part of a roster revamp.
There is still a question mark over the future of Russell Packer and Josh Reynolds at the club, while NSW winger Josh Addo-Carr is considering a four-year-deal from 2021.