Paul Gallen could join Andrew Ettingshausen as a 300-game one-club player with Cronulla, after re-signing with the Sharks on Wednesday.
Skipper Gallen has committed to a 17th NRL season with Cronulla after signing a new one-year deal ahead of Friday's preliminary final against North Queensland.
Gallen, 35, has played 277 games with Cronulla since making his NRL debut in 2001. He said 2017 would likely be his final season in the Shire.
"There was never any doubt I was going play next year and it will probably be my last year," Gallen said.
"I love the club and I love the area.
"We are in a really good position at the moment to hopefully make the grand final and win our first premiership.
"Friday is the most important game of my career."
Gallen missed the Sharks' qualifying final win over Canberra two weeks ago due to a back injury. But he will lead them in their quest for a grand final spot against premiers the Cowboys at Allianz Stadium.
"I am fine, no dramas at all," he said.
"I did full training on Tuesday and did most of the session on Sunday. I will do our captains run tomorrow and will be fine."
Gallen said the week off, a luxury the Cowboys didn't earn, has served the Sharks well.
"Everyone is really well, the week off has done us good," he said.
"A few of the older blokes like myself, Mick Ennis and Luke Lewis have really benefited.
"We will be really, really fresh on Friday.
"The Cowboys will come out to blow us off the park early on Friday. I think that is the only way they can beat us and if we can combat that we should win."
Sharks boss Lyall Gorman welcomed Gallen's contract extension.
"It is exciting news for the club and for Paul, everyone knows he is our spiritual leader," Gorman said.
"There has been no greater clubman here at the Sharks."
Club legend Ettingshausen played 328 first grade games for Cronulla between 1983 and 2000.
