On paper, 2017 seems like a very typical Tom Brady season. He is leading the NFL in passing yards and sporting a 102.8 passer rating that’s his second-best since 2011. The Patriots are once again the No. 1 seed in the AFC, and Brady is the leading candidate to be named the NFL’s most valuable player.

But over the past five weeks, there has been some trouble brewing in Foxboro — at least by New England’s own ridiculous standards. After the Patriots traded away Brady’s heir apparent, Jimmy Garoppolo, an ESPN report of an internal power struggle between Brady, coach Bill Belichick and owner Robert Kraft has clouded the future of the five-time champions. But perhaps more worrisome than this report is that Brady himself has been quietly marred in a slump.

Brady’s last five games of the 2017 regular season were uncharacteristically mediocre, despite New England going 4-1 in that span. Beginning in Week 13, Brady has posted a passer rating of 81.6, 17th best in the NFL, and his yards per attempt in that span were 6.95, 15th best in the league. He’s also been far worse in touchdowns to interceptions, going from 26-to-3 in his first 11 games to an unusual-for-him 6-to-5.

In the context of his career, Brady’s extended sample of poor play is surprising but not unprecedented. Dating back to 2007, when he turned 30, this is Brady’s sixth worst five-game stretch measured by expected points added based on the quality of his play. Brady accumulated 22.16 EPA in his last five games, for an average of 4.43 per game. His average in Games 1 through 11 was more than 2 points higher (6.76 EPA).

Brady’s worst five-game stretches Tom Brady’s lowest cumulative expected points added (EPA) in any five-game window, 2007-2017 Season From To Action Plays Total EPA Patriots Record 2010 10/4/10 11/7/10 195 18.14 4-1 2015 12/6/15 1/3/16 204 18.59 2-3 2013 9/29/13 10/27/13 216 18.74 3-2 2014 9/7/14 10/5/14 202 19.54 3-2 2009 11/22/09 12/20/09 184 19.81 3-2 2017 12/3/17 12/31/17 207 22.16 4-1 2015 10/29/15 11/29/15 226 22.19 4-1 Does not include overlapping periods or playoff games; single-season stretches only. Action plays include pass attempts, QB runs and sacks. Source: ESPN Stats & Information Group

Yes, Brady was without his best weapon, Rob Gronkowski, for the worst game in the stretch, a 27-20 loss to the Dolphins in Miami, when he managed only a 59.5 rating and 4.16 EPA. But he capped the regular season at home against the New York Jets with his lowest yards per attempt of the year (5.14), with an active Gronkowski being held catchless.

This could all be random variance. Maybe Brady is still eluding Father Time better than any quarterback in history and will soon erase all doubts, as he has before. He’s certainly fired up about even faint whispers of his decline. And the Patriots last year reportedly were planning as if his commitment to diet and training would allow him to play at an elite level for at least another couple of seasons. Brady, of course, seems to think he can continue pushing defenses around even when he’s pushing 50.

But if we were to look at the half-empty glass, we can draw comparisons to the career arc of Brady’s former longtime nemesis, Peyton Manning. No, not the Manning we last saw in 2015, who somehow won a Super Bowl with play so poor that his league-leading defense was forced to overcome it. Brady’s 2017 season is actually eerily similar to the 2014 Manning, who was his typical dominant self for the first 11 games of the year before falling off a cliff that can be seen now only in hindsight. At the time, the poor play was attributed to nagging injuries and not the inevitable end of one of the NFL’s greatest careers.

Neither quarterback gave any indication that anything was different if you look at the full-season statistics. But while we think a decline for a player happens neatly at the start of a season, Manning showed the circus can leave town at any time. For him, that time was his 12th game of the 2014 season. Previously, he was characteristically crushing the NFL with a third-best 109.5 passer rating and fourth-best 8.05 yards per attempt — that’s very similar to Brady’s first 11 games this year, with a 111.7 passer rating (first) and 8.27 yards per attempt (third).

But then Manning instantly transformed into an old quarterback: a 78.7 rating (24th) in his final five games with a TD-to-interception rate of 5-to-6, compared with 34-to-9 in the first 11 games.

Manning’s 2014 season ended with a home loss in the divisional round because of his poor play against an inexperienced playoff team with a third-year quarterback (Indianapolis’s Andrew Luck). Coincidently on Saturday, the Patriots will also take the field as a significant favorite at home against an inexperienced playoff team with a third-year quarterback (Tennessee’s Marcus Mariota).

Premature obits have been written for Brady before. There’s little reason to doubt New England based on what they’ve accomplished this century. But if Belichick and Brady are to get that unprecedented sixth ring, they will need Brady to look more like what he’s been and less like what he is: a 40-year-old quarterback.

Check out our latest NFL predictions.