Katoa thanked people for their messages and prayers, and the Storm club for its support.
“A special thank you to the Storm for all of the help and support that you guys are continuing to provide, I appreciate it,” he wrote.
Katoa made specific mention of the Tongan team after criticism of their handling of a pre-game collision with teammate Lehi Hopoate, which also featured on TV coverage.
Melbourne will receive salary cap dispensation to replace Katoa next season, with former Knights enforcer Jack Hetherington linked to the club.
“To all of my family, thank you for the love and support,” Katoa wrote.
“To the (Tonga Test team), the team that we love. I wanna (sic) say a massive thank you. The quality time that we had in camp was unreal.
“Thank you guys for the help in camp! I love playing for our little Kingdom.
“To my girl (partner), this woman has been amazing, strong and sticking by my side through it all. I appreciate you and I love you so much.
“A special thank you to the Storm for all of the help and the support that you guys are continuing to provide, I appreciate it.”