When Jimmy Butler rolled his right ankle on New York Knicks wing Josh Hart late in Game 1 of the Eastern Conference semifinals, cameras caught Miami Heat head coach Erik Spoelstra muttering, "F***." His reaction echoed the sentiments of so many: The eighth seed stood no chance without its best player.

Indeed, the Knicks tied the series in Butler's absence, before he returned on five days' rest for Game 3. He has averaged 40 minutes in 13 games since, ousting New York in six games, capturing MVP honors in a seven-game conference finals win over the Boston Celtics and helping the Heat return home tied 1-1 with the Denver Nuggets in the NBA Finals. It is hard to argue Butler's injury has hindered his team's success.

That does not mean it will be a non-factor in what is now a best-of-five battle for the championship.

Prior to this series, Yahoo Sports' Vincent Goodwill asked Butler last week at the annual media day for the Finals, "How is your ankle? You injured it against the Knicks and you tweaked it a little bit in Game 7. Are you 100 percent? Are you close to 100 percent? Is that a look that tells me you're going to lie right now?"

"No, I'm not going to lie. I'm going to say nobody cares. You don't, either," Butler joked to Goodwill during the session. "I'm still expected to do my job at a high level if I take the floor, which I will. We're going to be OK. We're going to get the job done, bum ankle or not, and I'm not taking a follow-up, so don't do that."

There are several ways to interpret that, but "bum ankle, and I'm not taking a follow-up" sure sounds like a player known for his toughness conceding no excuses, even if he has played 10 of his 13 games since the sprain on one day's rest. As Spoelstra said immediately after the injury, "You just don't know with ankle sprains."

Statistical evidence supports the notion that Butler is not at full strength. In a five-game, first-round victory against the Milwaukee Bucks before spraining his ankle, he averaged 37.6 points on 59.7% shooting from the field and 9.6 free-throw attempts, making better than half of his shots in each outing. In 11 games on either one or two days' rest since the injury, he is averaging 22 points on 40.6% shooting and 7.3 free-throw attempts. His production has surged to 31.5 points on 45.6% shooting and 10.5 free-throw attempts in two games on four or five days rest since the sprain. He has made 50% of his shots once since Game 1 against the Knicks — a 5-for-10 effort in a Game 5 loss to the Celtics, his lowest field-goal total of the postseason.

Call his jump-start against the Bucks unsustainable. Blame his performance on the injury or fatigue from a 33-year-old who gives every ounce of himself to each possession, but there is no denying something is amiss. Most notably, this: He made 72.7% of his 12.8 attempts per game from inside the paint before the sprain and has shot 44.2% on 10.6 attempts in the paint since. The eye test supports this, too, as he has hesitated testing taller defenders at the rim in recent weeks, often passing out of his patented pump fake.

Butler has tapped the reserves of his iron will when Miami has needed him most. He scored 17 of his 28 points in the second half of Game 7 against Boston, and in three quarters that flipped a trio of come-from-behind victories — a 46-point third quarter in Game 1 of the conference finals, a 36-point fourth quarter the following game and another 36-point fourth quarter in Game 1 of the Finals — Butler averaged 9.7 points on 10-of-18 shooting (55.6 FG%), better numbers than any fourth-quarter player during the regular season.

Spoelstra vacillated between suggesting Butler is carrying the same burden as he did pre-injury and implying Miami's role players have assumed a greater onus.

"He is doing it on both sides of the floor," Spoelstra told reporters Wednesday. "He has an incredibly tough cover defensively; that matters. Offensively, I still think we have a great place where everybody feels settled. If your role players can step in and start playing great, it's usually because they feel a confidence level from the best players, and that's Jimmy and Bam [Adebayo]. They infuse all of our guys to be aggressive.

"The way [the Nuggets] defend, they're prioritizing protecting the paint against [Butler], so he has to make the right reads. Down the stretch, those were his best moments. That's key for us in close games. However many points he had in the last six minutes, his fingerprints were all over the game down the stretch."

Still, Butler clearly tweaked his right ankle in the third quarter of Game 7 against the Celtics, and he is 13-for-33 from the field (39.4%) and has attempted 5 free throws through two games of the Finals. He has turned into more of a facilitator, averaging almost twice as many assists as he did in the Milwaukee series.

"Keep playing basketball as far as I can," Butler said after shaking off a 4-for-14 start to score 8 points on 5 shots in the fourth quarter of the Heat's rally against the Nuggets in Sunday's Game 2 of the Finals. "Making plays for others. Score whenever I get the opportunity to do so. And through all else, just find a way to win. I think we did that tonight as a group, and we'll continue to do that as a group."

It is remarkable that the Heat — owners of a negative point differential during the regular season — are in this position, given Butler's fading brilliance. They are +0.8 points per 100 possessions with him on the floor since the injury and +9.3 points per 100 possessions with him on the bench. Through two Finals games, Miami is +6 in 33 possessions without Butler and -14 in 145 possessions with him. It feels impossible that the Heat can carry that margin to a championship, but everything this No. 8 seed has done feels infeasible.

Maybe Miami can continue catching fire from 3-point range and rely on sudden bursts from Butler to carry them to three more wins and a ring. Maybe the two days off between all games but 3 and 4 of this series will help him gain more strength. Maybe the Heat run out of gas against yet another team more talented on paper. If Miami does have an extra gear to find in these Finals, it could turn on the health of Butler's ankle.