At the conclusion of his contract, Kelly was not re-signed by the Senators, making him an unrestricted free agent. Unsigned over the summer, the Edmonton Oilers signed Kelly to a professional tryout on September 9, 2017. Kelly attended the Oilers training camp and pre-season and remained with the club to start the 2017–18 season. Despite practicing with the team, Kelly was not offered a contract with the Oilers and on November 24, 2017, he returned within the Senators organization by signing a professional tryout deal with new AHL affiliate, the Belleville Senators.