By Michael Hurley, CBS Boston

BOSTON (CBS) — The last time the Patriots and Chiefs met, it was an old-fashioned Wild Wild West shootout, with old sheriff Tom Brady and young gun Patrick Mahomes going throw-for-throw in a 43-40 duel that was not decided until the final seconds. Now that they’re set for a playoff rematch, many might be expecting a repeat performance.

They probably should not.

While yes, playoff football is unpredictable, there are a number of reasons to expect a much different kind of game this time around. For one, that game took place on a 45-degree night in October. Sunday’s forecast calls for an “arctic blast” in Kansas City. That may change things a bit.

But even bigger a factor than the weather might be opportunity. And for the Patriots, that opportunity should come on the ground.

That was, in part, the case last time the two teams met. Sony Michel ran for 106 yards and two touchdowns on 24 carries. James White and Kenjon Barner tacked on another 55 yards on nine combined carries. That story line got somewhat washed away by Tom Brady throwing for 340 yards and a touchdown, and by Brady winning the game with consecutive passes to White and Rob Gronkowski that gained 55 yards in a matter of seconds.

At that point in the year, the 173 rushing yards allowed by the Chiefs’ defense was not even their worst effort of the year. The Niners had run for 178 yards in Week 3.

But since then, it’s only gotten worse for the Kansas City run defense.

The Broncos gashed them for 189 yards. The Raiders ran for 171, a week before the Ravens ran for 194 yards. Even without Melvin Gordon and Austin Ekeler, the Chargers ran for 119 yards during a win at Arrowhead. That preceded the worst outing of the year for the K.C. run D, as Seattle waltzed for 210 yards on the ground in Week 16. The season ended with Doug Martin picking up 100 yards on 21 carries.

All together, the Chiefs finished the year as one of the very worst teams in the NFL at stopping the run. By any way you measure it, the Chiefs were dreadful.

Chiefs Rankings: Run Defense

Yards allowed per attempt: 31st, 5.0

Yards allowed per game: 27th, 132.1

Touchdowns allowed: T-29th, 19

Those numbers are bad on the surface; very bad, in fact. But they’re even worse when you consider that with the No. 1 offense in the NFL, the Chiefs were often playing with a significant lead throughout the year. The fact that opponents still managed to run with such ease speaks to a complete inability by the Chiefs to stop the run at all.

The Colts only ran for 87 yards last week, but that is a number that’s deceiving. The yardage is so low because the Colts dug an early hole and abandoned the run. But they gained those 87 yards on just 14 rushing attempts — good for a 6.2-yard average per attempt. For perspective, the best rushing team in the NFL gained an average of 5.1 yards per attempt this season.

So, in limited bursts, the Colts’ rushing offense was better Saturday than the best rushing offense in the NFL during the year. And now, the Chiefs’ defense will be up against a team that is feeling confident about its run game.

Really, there’s no other way to feel after Sunday’s steamrolling of the Chargers. In that game, Michel rumbled for more than 100 yards and three touchdowns before halftime. Rex Burkhead added another touchdown on the ground, and the Patriots collectively ran for 155 yards and four touchdowns against a Chargers team that allowed the sixth-fewest rushing touchdowns and ranked ninth in the NFL in rushing yards allowed this year.

Now that same rushing attack — led by Michel but powered by the offensive line, along with James Develin, Rob Gronkowski and Dwayne Allen — gets to take on one of the worst run defenses in the league. The opportunity is a huge one for the rookie first-rounder.

Of course, if that were the Chiefs’ only defensive weakness, then it would perhaps not portend doom for Kansas City. Alas, the Chiefs ranked 31st in passing yards allowed, too, and they allowed 30 passing touchdowns, which was tied for ninth-most in the league.

Put it all together, and the Chiefs allowed the second-most yards in the entire league, while allowing the ninth-most points. Kansas City’s is by far the worst defense remaining in the postseason. If you give Tom Brady, Josh McDaniels and Bill Belichick a week to prepare for a defense full of vulnerabilities, the results typically aren’t great for the opposition.

Of course, a number of other challenges will be awaiting the Patriots; namely the Chiefs’ top-rated offense. The MVP at quarterback, and the fastest-man-alive Tyreek Hill, will make for a tough day for Belichick’s defense. Add in the world record potential for crowd noise, and New England’s mystifying struggles on the road this season, and this will be no picnic for the Patriots. And that point can’t be overstated, as eight of the Patriots’ 10 games with 100 or more rushing yards came in the friendly confines of Gillette Stadium. On the road, the Patriots turned in their six worst rushing performances of the year.

That may factor in come Sunday night, but this time of year, what’s happening recently tends to be more relevant than what happened in September and October. And for the Patriots, that should mean plenty of room to run whenever and however they want against the Chiefs.

You can email Michael Hurley or find him on Twitter @michaelFhurley.