The decision was apparently made by head coach Mike Singletary.
"After an evaluation period I felt it was best to go in a different direction," Singletary said in a statement. "This was not an easy decision because I appreciate Mike Martz, and I enjoyed working with him. He is a true professional, and I wish him the best in the future. I do recognize the need for a long-term solution on the offensive side of the ball."
It is believed that Singletary will look for a replacement with a run-first mentality, as the team looks to get back to smash mouth football.
With a healthy Frank Gore in the backfield and Vernon Davis at tight end, who Singletary recently said was the best blocking tight-end he’s ever seen, the team will have a chance to be an imposing force on the ground.