Watson has owned the Warriors since 2000 and been at the club's helm for the entirety of Mannering's 13-year 227 game career since he debuted in 2005.
The 30-year-old former club captain said Watson deserved credit for having invested heavily in the Warriors and his work in helping to grow and promote the club and the wider national game.
But with the Warriors already destined to miss the playoffs for a sixth-straight year, Mannering conceded something needed to change to break their finals drought.
"I can't really comment on it right now, but he's obviously done so many great things for the game in New Zealand from when the Warriors were doing it really tough," he said.
"If that is the case (that Watson does sell the Warriors) I'm sure we'll look back fondly on what he's done for the club.
"Obviously we need a change because it's been five, six years now where we've out of the playoffs, and that's too long for a club, any club, especially with the roster we've had over the years."
The Warriors have now lost their last six games and currently sit in 12th spot on the NRL ladder with just seven wins from 21 matches. They last enjoyed victory with a seven-point win over the Bulldogs in round 16.
They now look ahead to Friday's away clash with the Rabbitohs in Sydney with two more matches to follow against Manly and Wests Tigers.