Former Rangers, Chelsea striker Spencer leaves role as Houston Dynamo assistant
The departure of Spencer will be seen as a huge loss to the Texan club as he brings a wealth of experience and knowledge to the squad.
Kinnear admitted that his former number two would be hard to replace.
"I'll miss him and I loved working with him," Kinnear said. "You always appreciate an assistant coach who has so much knowledge where individual players would come up to him and ask for advice because they know he knows what he's talking about."