The brilliant centreman told the Zebras increasing work commitments would prevent him from playing on.
â€œYes, itâ€™s a big blow,â€ Sandy general manager John Mennie said.
Summers told The Leader he had a heavy heart as he phoned president Gerry Ryan and coach Andy Lovell to inform them of his decision.
He said he had always enjoyed his time at the club, had been part of a wonderful era and made many friends.
â€œIt was tough making the calls but youâ€™ve just got to take the emotion out of it,â€ Summers said.