The club are currently rock bottom in the 13-team S-League table, having lost all their three matches since the start of the 2012 Great Eastern-Yeo's S-League.
The changes come as former international Leong Kok Fann promised to usher in a period of stability after taking over as club chairman from long-time football administrator Patrick Ang, who retired in late January, two weeks before the start of the 2012 season.
Ang's departure followed closely the exit of Robert Lim and former international Seak Poh Leong from the club.
Speaking to TODAY Geylang general manager Lim Tong Hai said: "We're not sacking Mike, he's still within the club setup, managing the Prime League side. This is part of the rebuilding and renewal process at Geylang United."
The club's decision to appointment him as the new coach of their S-League side took Kanan by surprise.
"This came out of the blue, I was only told last night that I would be taking over the S-League squad, and I've to say that I'm surprised that this has happened so early in the season," Kanan told TODAY.
Added the coach who led Gelyang to the 2011 Prime League title: "This is a big challenge for me. We've lost three games, and face a tough match next, away to DPMM. The first thing I've to do is inject some confidence in the squad, especially after losing 7-1 to Home."
TODAY understands Wong is seeking clarification from the club, and is unlikely to accept the role of Prime League coach.