Ola signed with the Dolphins in January after spending two seasons in the Canadian Football League with the Montreal Alouettes. Bears coach Marc Trestman served in the same capacity with the Alouettes during Ola’s first year with the team in 2012.
Martin signed with the Bears last Nov. 13 and played in the final seven games, recording six tackles on special teams and one stop on defense. He has appeared in 73 NFL games over eight seasons, also playing for the Ravens (2006-08), Packers (2009-10), Giants (2011) and Patriots (2012).
Gaines spent his entire rookie season on the Bears’ practice squad last year after signing with the team as an undrafted free agent from Tennessee State.