Stewart, 30, moved to the Lions late last week and was immediately thrust in to action by Swinton first team coach Paul Smith.
Director of Coaching Paul Kidd told the club’s official website: “Due to the high level of injuries at the moment, this a great signing for us. Tony has played at the highest level in this country and his experience can only help.
“Tony had yet to find a club, but to have a player of his calibre, willing and able to step up is fantastic.
“Tony was keen to get back in the game and knows he will have to work hard to cement his place in the team and is looking forward to the challenge.”