Don Matthews went 0-8 in his third stint as the Argos' head coach. ((Nathan Denette/Canadian Press))

Don Matthews, the CFL's all-time winningest coach, resigned from the Toronto Argonauts on Friday, saying his days on the sidelines are over.

Matthews, 69, lost all eight games he coached after returning in September for his third stint with the Argos.

Taking over for Rich Stubler, who was fired after going 4-6 in his first year on the job, Matthews was at the helm as the Argos finished 4-14 and missed the playoffs for the first time since 2001.

Toronto's season ended with a 45-38 home loss to Saskatchewan on Thursday night.

"Our owners are very passionate people, and I wish I could have given them more, because they live and breathe football," said Matthews.

He plans on returning to Oregon and resuming his retirement.

"I think my time has come," he said.

Matthews is the CFL's all-time leader with 231 regular-season wins, and is tied for the most Grey Cup victories with five. He earned another five championship rings as an assistant coach with Edmonton from 1978 to 1982.

He coached Toronto in 1990 and from 1996 to 1998.

Matthews had been out of football since 2006, when anxiety issues forced him to step down as head of the Montreal Alouettes.

In the ensuing years, he found a medication that helped control his anxiety and felt ready to resume coaching when the Argos came calling in September.

With files from the Canadian Press