I don't think that's quite right Frodo. Otherwise you would call it a player option or club option. A mutual option would indicate bot parties need to agree.
From the NRL website:
Queensland Origin and Test player Selwyn Cobbo will add even more firepower to the Dolphins’ backline after agreeing to a one-year deal for NRL season 2026.
www.nrl.com
Player option (PO): Player has the option to activate additional year(s)
Club option (CO): Club has the option to activate additional year(s)
Mutual option (MO): Both parties discuss the option to activate additional year(s)