ESPN's Football Power Index rankings for Oct. 6

Chancellor: It's never over 'til you cross that end zone

Seahawks S Kam Chancellor breaks down his game-changing fumble against Calvin Johnson, which helped seal Seattle's 13-10 win over Detroit.

Below are the ESPN Football Power Index rankings for Oct. 6, after Week 4 of the 2015 NFL season. For a full explanation on how the FPI is put together, please read this explainer. For more background, you also can read this Q&A.

A few notes heading into Week 5:

The Detroit Lions’ controversial loss on Monday Night Football didn’t help their playoff chances any, but the performance did result in the team improving in ESPN’s Football Power Index.

Despite a 13-10 loss to the Seattle Seahawks, the Lions’ FPI rating rose 0.6. The Lions moved up two spots in the FPI rankings to No. 23.

FPI gives the Lions a 4.6 percent chance to make the playoffs, eighth worst in the league.

The Atlanta Falcons (4-0) and the Cincinnati Bengals (4-0) made two of the biggest jumps in FPI after Week 4 and have solidified their chances of making the playoffs.

The Bengals posted a season-high offensive efficiency of 98.2 in Sunday’s 36-21 victory over the Kansas City Chiefs. Their FPI rating rose 1.3 to plus-4.1 -- meaning they are projected to be about four points better than an average NFL team on a neutral field -- and they moved from 10th to fifth in FPI rank.

In the Falcons’ 48-21 victory over the Texans, Atlanta’s defense earned a 94.5 efficiency, the Falcons’ only above-50 showing in defensive efficiency this season. An increase of 2.4 points in the Falcons’ FPI put them at plus-3.8, moving them from 13th to seventh in the rankings.

The Falcons entered the season with a 40.8 percent likelihood of making the playoffs, and the Bengals with a 42.1 percent likelihood. Now, the Falcons have a 96.8 percent likelihood (second to the 97.3 of the Green Bay Packers), and the Bengals are at 89.9 percent (the fourth-best chance in the NFL).

Looking to Week 5, the Seahawks’ road game against the Bengals is expected to be the week’s best, according to FPI. It has a pregame matchup quality of 75.3.