In the three seasons since joining the Denver Broncos, quarterback Peyton Manning has been the highest-scoring player in fantasy football. His 2013 season saw him post fantasy numbers that might never be topped. However, 2015 will see a significant enough drop-off in his fantasy numbers to knock him from the ranks of elite fantasy quarterbacks.

This is not a prediction of how Denver or Manning will play this season. The Broncos will be content to win games 20-10 with Manning throwing one touchdown versus a 38-35 loss with him throwing five. However, the latter is obviously the more desired outcome for fantasy owners of Manning, who don't care if the Broncos win or lose.

My prediction of Manning's fantasy drop-off is based on two things — age and a new coaching staff and offensive scheme.

He is 39 and history shows that quarterbacks that old don't succeed on the field on in fantasy. On the field, no quarterback older than 38 has ever reached the Super Bowl, let alone win one. It's not much better in fantasy. As Michael Fabiano of notes, only two quarterbacks 39 or older who started at least 10 games have averaged more than 16 fantasy points. From 2012-14, Manning averaged almost 30 points a game.
While I don't see his production being cut in half, I would see him averaging closer to 24 a game, which in that three-year span would have made Manning a borderline Top 10 fantasy quarterback in my fantasy league, not a Top 3 like he has been.

In addition to Manning's age, I base my estimates on his new coaches. Out goes John Fox, a defensive coach who left running the offense to Manning and his offensive coordinators Mike McCoy (2012) and Adam Gase (2013-14). Under Gase, Manning averaged 33 points the last two seasons. The new Broncos head coach is Gary Kubiak, a former quarterback, who is taking a hands-on approach to the offense.

Gone will be the emphasis on the passing game and in its place will be Kubiak's beloved zone blocking scheme, which emphasizes running the ball and will have Manning taking snaps much more under center than in his preferred shotgun. Running backs love the scheme, as do their fantasy owners. Kubiak's system made stars out of Arian Foster in Houston (where Kubiak was the head coach) and with Justin Forsett last year (where Kubiak was offensive coordinator). If Kubiak names a starter in Denver who will take the lion's share of carries — either C.J. Anderson or Montee Ball — I would snag that player as one of my two running backs.

Quarterbacks, from a fantasy standpoint, have not thrived under Kubiak. From 2012-14 when Manning was averaging 30 fantasy points a game, Kubiak's quarterbacks in Houston and Baltimore averaged 19. That's a big difference. Granted, Kubiak had the likes of Matt Schaub, T.J. Yates and Case Keenum in Houston and combined those three don't come near Manning's talent. But in 2014, Joe Flacco was his quarterback and he averaged only 20 points a game, good for 16th in my league.

Kubiak's mission is to win games and not produce fantasy points. His goal is to keep Manning healthy for the playoffs. That is harder for an older quarterback, who wears down faster as the season progresses (Manning had ankle injuries in 2013 and hurt his quadriceps last year). In addition, the offensive line is a potential mess, with at least three new starters from a year ago. Running the ball more might help keep Manning upright. Manning is also missing three targets — tight ends Julius Thomas and Jacob Tamme and receiver Wes Welker — who had a combined 40 touchdowns the past two seasons. That's a lot of fantasy points no longer in Denver.

Add up age, a new offensive scheme and loss of key receivers and it's hard to see how Manning comes anywhere close to his numbers the past three seasons. There will be at least six quarterbacks with better fantasy production this season (Andrew Luck, Aaron Rodgers, Tony Romo, Ben Roethlisberger, Drew Brees and Matthew Stafford) and that list could be longer if players like Russell Wilson, Cam Newton, Ryan Tannehill and Matt Ryan have everything click in their offenses. Draft Manning and you will get consistent numbers, just not elite.

Peyton Manning is my all-time favorite athlete and I will be rooting for him to go 19-0 and win a Super Bowl. I don't care how Denver wins, just as long as they do. But in my fantasy leagues, I am looking elsewhere for a starting quarterback.