FOXBOROUGH — In football terms, the Patriots and 49ers are relative strangers. AFC and NFC, East and West. Both have been to the Super Bowl since Dec. 16, 2012, the last time the teams met, and both rosters have changed dramatically since then.

The players who remain, though, remember that game well.

“Oh it was cold,’’ 49ers tackle Joe Staley said Wednesday. “It was cold. That’s the main thing, it was cold. It was like 37 degrees and raining hard, I remember it was almost to the point where it was like icicles on your face mask. But I mean yeah, it was a crazy game.’’

The game was on “Sunday Night Football,’’ broadcast from freezing Foxborough. The Patriots entered the game 10-3, battling the Broncos for playoff position. The 49ers were 9-3-1 and riding the hot hand of quarterback Colin Kaepernick, who had been Alex Smith’s backup until Smith suffered a concussion in Week 10. Ed Hochuli was the referee.

The game was epic. The Patriots fell behind, 31-3, midway through the third quarter before scoring 28 straight points to tie the score at 31.

“They came back in the fourth quarter and all of a sudden it was like, ‘We have to score or else they’re going to go back and win the game.’ You can never relax when you’re going against [Tom Brady],’’ Staley said. “That’s why you play the game. You play the game to play against the best and he’s certainly the best.’’

But after tying the score, the Patriots gave up a 62-yard kickoff return to running back LaMichael James and a 38-yard touchdown from Kaepernick to wide receiver Michael Crabtree, then couldn’t get a first down on the following drive. Brady couldn’t complete a fourth and 1 to Danny Woodhead.

Both teams traded field goals but, down by one score with 38 seconds to play, the game effectively ended when the Patriots couldn’t convert an onside kick. New England lost, 41-34, despite 520 yards of total offense, and San Francisco completed a sweep of the AFC East.

“It was an interesting game just the way it all unfolded with them taking a big lead and us coming back down the end and them making a big play to end the game,’’ said safety Devin McCourty. “But just what [Kaepernick was] able to do on the field. I think at that time, everyone was kind of taking notice.’’

Kaepernick himself recalled to reporters in San Francisco Wednesday how getting a road win in December boosted his confidence.

“It was a great feeling to go up there, get that victory, especially against a team like that. It was huge,’’ Kaepernick said.

Smith never regained his job and Kaepernick quarterbacked the 49ers to Super Bowl XLVII, where they lost to the Ravens.

Things, however, went downhill from there. Kaepernick has not become a franchise quarterback and Jim Harbaugh, the 49ers coach at the time, is now the coach at Michigan. After a year under under interim head coach Jim Tomsula, the 49ers hired Chip Kelly, who had been fired in the offseason as coach in Philadelphia.

Bill Belichick counts Kelly among his friends, and, at the time, said it was “really disappointing’’ to see a “great coach’’ fired.

On Wednesday, Kelly said he was grateful for the support.

“Bill has been a great friend of mine dating back all the way to my time at New Hampshire, so I was just very thankful that he is a friend of mine and I’ve got great respect for him,’’ Kelly said on a conference call.

Kelly also joked about how the two keep in touch.

“We’re Facebook friends,’’ he said dryly. “We spend a lot of time online together.’’

Kelly himself has played the Patriots much more recently than his new team, just last season with the Eagles.

The Patriots were coming off their first loss of the season, in overtime in Denver, and were favored by 8 points over the 4-7 Eagles, but put together an uncharacteristically sloppy performance, particularly in the kicking game, where they allowed an 83-yard punt return for a touchdown by Darren Sproles, and lost 35-28.

Perhaps even more than the 49ers game in 2012, the game has come up a lot this week.

“Yeah, [Belichick] has been on us about that game, too,’’ McCourty said. “Obviously, we didn’t do some things well that game, so we just talked about the importance of, with Chip Kelly being there now, they’ll definitely probably go through that game, and things that they gave us trouble with they’ll look at and probably go back to.’’

It doesn’t matter that Kelly has switched teams, Belichick still expects him to run a similar scheme in San Francisco, so the tape from the Eagles game is relevant.

“Yeah, absolutely. Yeah, that’s a good game to watch. I mean I’m sure that’s the one he’s starting with out there. They hurt us doing a lot of different things. I’m sure we’ll see some elements of those schemes again,’’ Belichick said.

“I can’t imagine they wouldn’t test us out and see whether we can handle it. We didn’t handle it very well last year, so yeah, same thing in the kicking game. It’s basically their same scheme on special teams that they ran in Philadelphia so I’m sure we’ll get tested in those areas as well. I can’t imagine we wouldn’t.’’

The NFL is such a patchwork of one-year contracts and domino effects, it doesn’t take long to find common threads between teams that haven’t played each other in an entire election cycle.

Where there’s familiarity in the spots that matter most, quarterback and head coach, everyone has history.

Nora Princiotti can be reached at nora.princiotti@globe.com. Follow her on Twitter at @NoraPrinciotti.