By Chad Finn, Boston.com Staff

When the Patriots make their preseason debut August 9, a voice that accompanied generations of fans on autumn Sundays for more than three decades will be absent from the team’s radio broadcast.

Gino Cappelletti, known affectionately as “Mr. Patriot” for his on-field exploits during the franchise’s early years before embarking on a 32-year career as the popular color analyst on the team’s radio broadcasts, has decided to retire.

Gil Santos, his partner for 28 years on the broadcasts and the past 21 consecutively, will return for his 36th year in the booth. Scott Zolak, the former Patriots quarterback who thrived in an innovative sideline-based third analyst role last season, is expected to succeed Cappelletti on 98.5 The Sports Hub’s broadcasts, though that decision is yet to be finalized.

The gentlemanly Cappelletti, 78, was not available for comment Thursday night, but he said in a statement through CBS Radio that it has been tremendously rewarding to watch the Patriots develop into one of the NFL’s signature franchises

“Through five decades, my romance with football and my relationship with the Patriots organization have provided me with a lifetime of wonderful memories,” said Cappelletti a rookie wide receiver/kicker/defensive back on the franchise’s inaugural team in the American Football League in 1960 who would go on to be an MVP, a five-time All-Star, the league’s all-time leading scorer, and a member of the all-time All-AFL team.

“I have had the privilege of sharing the broadcast of six Super Bowls, and amazingly, five in the past decade. The memory of the first Super Bowl victory will always be fresh in my mind. For me, it serves as a special reminder of how far this franchise has come, the challenges that were met, and the adversity we faced in those early years. But as they say in the huddle after a long, successful day’s work, it’s time to take a knee and celebrate the win.’’

Santos and Cappelletti, paired together from 1972-78 and consecutively from 1991 through last season, had many successful days of work. With Santos’s classic baritone and Cappelletti’s genial manner, they were the unofficial voices of fall in New England. During their heyday Patriots fans liked to say they turned down the sound on the television so they could listen to the broadcasters they knew simply as Gil and Gino. Their call of Adam Vinatieri’s winning field goal in Super Bowl XXXVI remains an all-time classic.

But in recent years, the game seemed to speed up on Cappelletti, and gaffes became more prevalent during the broadcast. Adding Zolak to the team last year was a graceful way of providing support while letting Cappelletti go out on his own terms. But for generations of Patriots fans, it won’t be quite the same without him.

“Gino is a beloved sports legend in the region who has earned this well-deserved retirement,’’ said CBS Radio Boston senior vice president and market manager Mark Hannon. “Listening to the Patriots games without the voice of Cappelletti will be a big change.”