WHEN THE PATRIOTS RUN

Veteran LeGarrette Blount helped spearhead New England's offensive attack while Tom Brady served his four-game suspension, including back-to-back 100-yard performances in September. The Patriots have been far less reliant on the run game since Brady's return, which has also coincided with tight end Rob Gronkowski's return to full health, but Blount is still capable of being the focal point, as evidenced by his two-touchdown performance against Pittsburgh in which he topped 100 yards for the third time this season. That might be tougher to duplicate against Buffalo. Although the Bills, led by run-stuffers Zach Brown and Preston Brown, have struggled against the run, allowing Miami's Jay Ajayi to top the 200-yard mark last week, the Patriots went nowhere on the ground in Week 4. Obviously things change greatly with Brady back at the helm, but the Bills are capable of controlling the Patriots running game more than than Pittsburgh did.  Advantage: BILLS

WHEN THE BILLS RUN

Buffalo's ability to move the football on the ground depends on the availability and health of workhorse LeSean McCoy, who left last week's game with a hamstring injury, the same lingering injury that cost him four games a year ago. McCoy has enjoyed a resurgence in 2016 and ranks among the league leaders in rushing yards and all-purpose yards. He's the focal point of a running game ranked at or near the top of the NFL for most of the year. Without McCoy, the Bills would have to rely on Mike Gillislee, who averages better than 6 yards per carry despite limited touches. Like the Bills, the Patriots have been toeing the line as a top-10 run defense all year, even with Dont'a Hightower and Jamie Collins missing games due to injury. The big guys in the middle, specifically Malcom Brown and Alan Branch, have gotten the job done and with McCoy at less than 100 percent look for that to continue. Advantage: PATRIOTS

WHEN THE PATRIOTS PASS

Brady has been sensational since his return to the lineup in Week 5, and it's hard to imagine any defense slowing New England's progress at this point. Gronkowski is healthy, Martellus Bennett is feeding off his teammates' success and Chris Hogan and James White have carved their own roles in the passing game as Julian Edelman attempts to get up to speed. Since head coach Rex Ryan vowed to ditch the hybrid 3-4 defense that tempered Buffalo's aggressiveness a year ago, the Bills are back to being the pass-rushing juggernaut they were under Doug Marrone, ranking among the top five in the NFL in sacks per pass attempt behind resurgent vet Lorenzo Alexander (9 sacks) and Jerry Hughes (4 sacks). They're also elite in the red zone and on third down, a dangerous threat to any passing game, even one as stellar as New England's. But Gronkowski owns Buffalo, especially in Orchard Park, and Brady is locked in at the moment. Given the time, the Bills secondary doesn't have the answers. Advantage: PATRIOTS

WHEN THE BILLS PASS

Much like their running game, the Bills success in the passing game also depends somewhat on the availability of McCoy, who is one of the team's top three receivers behind Robert Woods and tight end Charles Clay. Woods is dealing with a foot injury as he tries to replace Sammy Watkins, making Buffalo even more limited in the passing game, and quarterback Tyrod Taylor ranks near the bottom of the league in passing yards and yards per attempt. Even big-play threat Marquise Goodwin is banged up. The Patriots are one of the league's top scoring defenses but have been dreadful in the red zone and are prone to giving up large chunks of yards against average quarterbacks. Without McCoy much of the burden will fall on Taylor's shoulder, and although he was efficient in Buffalo's Week 4 win at New England it's hard to imagine a repeat performance Sunday. Advantage: PATRIOTS

SPECIAL TEAMS

One of the keys to Buffalo's early-season win streak has been the play of its special teams, especially the coverage units. The Bills recovered a botched snap on a field goal against Arizona and turned it into a touchdown and also forced a fumble on a kickoff return against the 49ers. They blocked a punt in Miami a week ago as well. Their ability to shorten the field for the offense is critical, considering they lack depth at the skill positons. The Patriots always rank among the league's best in the return game, but veteran kicker Stephen Gostkowski has been shaky this season. He's already missed as many field goals this year as he did all of last season, and he's also missed extra points in back-to-back games. While the Patriots are historically efficient on special teams under Bill Belichick, the Bills are making more plays of late. Advantage: BILLS

OTHER FACTORS

This is still an intangibles game, and the Patriots almost always have the edge in that department when matched against division rivals. The Bills have played well in recent weeks and have crept back into the AFC East race. Considering they already beat New England once this season, the Patriots need to get this one back in order to avoid a tiebreaker scenario (as unlikely as that might seem). The one thing we've learned over the past decade and a half is that it's hard to pick against the Patriots in critical games. This is not a must-win in the traditional sense, but a victory Sunday gives New England even more breathing room in the division while it continues to find its identity on both sides of the ball. While past games might not mean much, it's worth noting the Patriots have won four in a row in Buffalo and 16 of their last 17. Advantage: PATRIOTS