Mikkelson had one assist in 19 games with Calgary last season after he was claimed off waivers from Anaheim in October. He agreed Thursday to a two-way deal worth $721,900.
Mikkelson, 24, has six assists in 86 NHL games. He was chosen by Anaheim with the No. 31 pick in the 2005 draft.
Reinhart had 34 goals and 45 assists with Western Hockey League champion Kootenay last season. He was chosen by the Flames with the No. 64 pick in last year's draft.