Olosunde made 72 appearances in the 2 seasons he spent with us, but is now looking for a new club.
Speaking to the clubs official website, boss Paul Warne wished him well; "On behalf of everyone here, I would like to say what a pleasure it has been to work with Matty for the last couple of years.
"As we try to with every player that comes through the door, we have worked on making him a better player than when he joined us and I hope that he agrees that we have been successful in doing so.
"He leaves the club with absolutely no animosity as he looks to pursue a new challenge somewhere else and goes very much with our blessing. Matty and his representatives felt as though it was time for a fresh start and are hopeful that he can secure a deal to continue playing in the Championship or at similar standard somewhere else in the world - something we totally understand.
"Matty is a good lad who has grown in confidence both on the pitch and off it and I hope that our footballing paths cross again in the future."