Per The Athletic's Stephen Holder, Rivers said Saturday he hopes to play beyond 2020, but "I don't think you'll see me in the Tom Brady range."
Rivers noted he considered retiring at the end of 2019 but decided against it because he believes in his ability.
"I think really where we settled in is I still love to play, certainly not coming off my best year [in 2019], but I know I still can play at a high level," Rivers said, per ESPN's Mike Wells. "... It was one of those deals where we said if there's nothing else out there then that'll be our answer. I don't want to just try to hang on to play."
Brady, who signed with the Tampa Bay Buccaneers, is entering his 21st NFL season and will turn 43 on Aug. 3. The three-time NFL MVP told ESPN's Ian O'Connor in May 2017 that he felt he could play well into his 40s.
"I always said my mid-40s," Brady said, "and naturally that means around 45. If I get there and I still feel like I do today, I don't see why I wouldn't want to continue."
At 38 years old, Rivers has a lot more football behind him than in front of him. He spent 16 seasons with the San Diego/Los Angeles Chargers. The eight-time Pro Bowler is the franchise's all-time leader in passing yards (59,271), passing touchdowns (397), wins (123) and completion percentage (64.7, min. 100 attempts).
Indianapolis is banking on Rivers to return to form next season. He completed 66 percent of his attempts last year, but his 23 touchdowns were his fewest since 2007 and 20 interceptions were the third-most in the NFL last season.
The Colts missed the playoffs in 2019 with a 7-9 record. The offense fell from fifth in points per game (27.1) two years ago to 16th (22.6) in the wake of Andrew Luck's retirement.