After extending his boxing record to 7-0, with a fourth round knockout of Ryan Carr-Ketu on Friday night, the Sharks skipper has turned his attention to his 17th and final NRL season.
As well as dealing with the departure of hooker Michael Ennis and fullback Ben Barba's hiatus from football, the Sharks are facing generational change in the back-row over the next few years.
Gallen, 35, will bring down the curtain on his career in 2017 while fellow forwards Luke Lewis, 33, and Chris Heighington, 34, are all nearing the final stages of their careers.
Coach Shane Flanagan has added youngsters Jaimin Jolliffe, Jayden McDonogh and Jayden Walker to Cronulla's top squad and Gallen thinks those players will get their opportunities.
"I might play a bit less minutes at times," Gallen told AAP.
"I'm getting a bit older now so but we've got a few good back-rowers coming up.
"We've got some real good outside backs. We've got to start blooding some young back-rowers. There's a couple of guys that can come up into first grade."
After defeating Carr-Ketu at Southern Cross Group Stadium on Friday night, Gallen called on Sonny Bill Williams to meet him in a super bout next year.
After an exhausting 2016, Gallen will have two weeks off before returning to training in preparation for the World Club Challenge against Wigan on February 19.
The Sharks workhorse had not ruled out making an appearance at the Auckland Nines but insisted that decision lay with Flanagan.
