Roll back the calendar a couple months, and things weren’t going so well in Oklahoma City. The Thunder had to open their season without former MVP Russell Westbrook, who was in the final stages of his knee rehabilitation following a late-summer arthroscopic procedure. And even after getting him back a few games in, the club struggled out of the gate, beginning 0-4 and becoming the last team in the Western Conference to claim its first victory.

Fast-forward to Christmas, the Thunder are currently one of the NBA’s hottest teams; winners in 21 of their last 28. Paul George has played MVP-level ball, averaging 32 points on 53 percent shooting the past few weeks. And Oklahoma City has the league’s second-best defense, a notable stat since Andre Roberson, perhaps the team’s best defender, has missed the entire season.

With OKC a game out of first in the West, and no one separating themselves as the top challenger to the Warriors, it’s time to ask: Have the Thunder become legitimate contenders?

The answer, to this point, is something of a mixed bag. Yes, the defense has been downright dominant at times, and their overall net rating suggests they belong in the conversation. But the offense — slightly below average, and still with considerable flaws beyond Westbrook, George, Steven Adams and Dennis Schroder — doesn’t enjoy that same level of success each night.

There’s no question about this team’s most abundant strength. Its imposing length and eye-popping athleticism stands out even more now, with Jerami Grant starting and Nerlens Noel and rookie Hamidou Diallo getting minutes off the bench (and without Carmelo Anthony as a weak link teams can attack relentlessly in screen-and-rolls). And aside from largely negating pick-and-rolls — third in efficiency against them — the Thunder get their hands on just about everything, ranking second in the NBA in deflections, and second in recovered loose balls. Oklahoma City is lightning quick and has a ton of collective hustle among its youngsters, making it tough to score even in situations that would normally present easy fast-break opportunities. One sign of that: After forcing a Thunder turnover, it takes opposing teams 9.4 seconds on average to get off a shot attempt, tied for the second-longest span in the NBA, according to Inpredictable.

The club addressed one of its biggest problems over the years — the awful bench depth — when it acquired Schroder in the deal to dump Anthony. But on some level, OKC’s main problem now is the same as it ever was: In a league where basically everyone can shoot from outside, the Thunder still struggle mightily from distance. They’re tied for second worst in 3-point accuracy, and Westbrook — while he’s cut down considerably on his long, midrange 2’s — is on pace to have one of the worst volume 3-point shooting campaigns of all-time, at just 23.6 percent on nearly five attempts from deep per game. As such, OKC ranks in the bottom 10 in effective field goal percentage, the lone contender in that group among several teams likely to make the lottery.

There’s obvious room for upside. Beyond the continued hope that Roberson will rejoin them at some point this season, the Thunder also have one of the youngest rotations in the NBA. They have seven players who are 25 or younger and have logged at least 300 minutes already.

If there’s a downside, it’s that Oklahoma City hasn’t been thoroughly tested from a scheduling standpoint yet. In fact, only Boston has played an easier slate to this point. According to a preseason BPI tracker, the Thunder’s projected winning percentage was expected to get progressively worse each month after December because of the escalating schedule to come. (Another possible challenge, though OKC would love to get Roberson back from injury, would be the potential spacing problems upon Roberson’s return. There’s already limited shooting on the floor, and his unwillingness to pull the trigger would further hinder the effort to fix that conundrum.)

Nonetheless, FiveThirtyEight’s newly updated projection model really seems to like the Thunder’s chances of becoming Golden State’s most viable challenger out West. Despite the incredibly solid Denver Nuggets’ turnaround, which has them virtually tied for first place, the system gives Oklahoma City a 10 percent probability of making it to the NBA Finals, more than double that of any other Western Conference team.

Time will tell whether those projections were merely an overshoot. But for the time being, after a slow start this season and two consecutive first-round flameouts the past two years, the Thunder will gladly take making it onto Santa’s nice list heading into their Christmas Day game.