MIAMI -- In late January, the San Antonio Spurs traded backup guard Bryn Forbes to the Denver Nuggets. Five months later, that unassuming move has made a major impact on the 2022 Eastern Conference finals.

It was the opening of an opportunity for the Boston Celtics that has been fully realized, as they have pushed the Miami Heat to the brink after a 93-80 Game 5 win on Wednesday and a 3-2 series lead.

It had been eight years since the Spurs were willing to work a midseason trade, and the Celtics held a minor part in it, acting as the third team in the deal. More importantly, it was the awaited signal that the Spurs were open to trades -- and the Celtics wanted in.

A few weeks, a bunch of phone calls and plenty of negotiations later, the Celtics pulled the sword from the stone and landed guard Derrick White.

This is not to say White is a main reason the Celtics are one win from their first NBA Finals appearance in 12 years. But having White, a starter-level guard who is a luxurious backup for a title contender, is a cornerstone of why Boston is in this position.

The East had the most competitive regular season in a generation. Four 50-win teams were separated by two games in the standings. A 44-win team (the Cleveland Cavaliers) didn't make the playoffs; there have been several years in the past decade when that got you the 5-seed in the East.

But injuries have diminished what promised to be a potentially all-time great East playoff bracket. Joel Embiid's torn thumb ligament, orbital fracture and concussion damaged the Philadelphia 76ers' chances of advancing past the conference semifinal round. Khris Middleton's knee injury very well might have been the deciding factor in the Milwaukee Bucks' seven-game series loss to Boston in the second round.

And now the Heat have been reduced to a partial output of their 53-win roster, with three of their best offensive players affected by injuries.

Kyle Lowry, who has played the past three games but as a shell of himself, went 0-of-6 in Game 5, and he is 5-of-23 in the series. His explosiveness has been robbed by a hamstring injury.

Jimmy Butler is playing on one leg, a sore knee halting his ability to get off a jump shot or get past defenders. After going to the foul line 26 times in Games 1 and 2, Butler has been there six times in the past three contests.

In Game 5, the Celtics essentially stopped guarding Butler. They backed off Butler and treated him as an unskilled screen setter, not the team's most dominant offensive player.

"Butler wasn't looking to score," Celtics coach Ime Udoka said. "We wanted to keep a big on him, play him like a big."

Over the past two games and all the while playing through knee inflammation, Butler is 7-of-32 shooting, marking the worst two-game shooting stretch of his career (with at least 25 attempts) per ESPN Stats & Information research.

Tyler Herro has missed the past two games with a groin injury. Even with these postseason stakes, the Heat wouldn't consider pushing Herro to play. Coach Erik Spoelstra said it would have been "irresponsible" to do so. Herro averaged almost 21 points a game this season, and that production has proved irreplaceable, as Miami has averaged 81 as a team over the losses in Games 4 and 5.

Back to that February deal. This is where Boston's preparation has saved them. Getting White has proved a vital addition, as Marcus Smart has missed three games this postseason with quadriceps, foot and ankle injuries. The Celtics are 3-0 in those contests. And on Wednesday, when Smart was limited and shooting 1-of-5, White had 14 points, five assists and two steals.

White was 5-of-6 shooting and scored 11 of the Celtics' 37 points in the first half of Game 5, nearly single-handedly keeping the team afloat. That was after his 13 points, eight rebounds, six assists and three steals in place of Smart in Game 4.

"Derrick, the last two games, has been fantastic. His contributions to our team have been great," said Jaylen Brown, who took over the starring role in Wednesday's second half. "He's been essential."

The Celtics are banged up themselves: Smart's right leg is a medical case study; Jayson Tatum is dealing with a right shoulder ailment that has caused him to throw up some atypically hideous shots; Robert Williams III is coming back from a late-season surgery and is daily battling a bone bruise in his left knee; and Brown is coming off of a hamstring injury.

But in Game 5, the Celtics had their full roster available for just the fourth time this postseason and the first time in the series. Brown, who had 25 points, and Tatum, who had a bad shooting night for 22, were the leaders, as usual. But the reason the Celtics won was because they just had more healthy players at the right times.

A big reason the Celtics have persevered is because of how the roster has been constructed for this gauntlet, the inserting of White and his ability to deliver within his role perhaps being the best example.

And, of course, fortune has played a part. Boston's previous two playoff opponents, the defending champion Bucks and now the top-seeded Heat, haven't been as well-equipped or quite as healthy.

Some like to point out that in certain years, the title winner should have an asterisk because injuries or other circumstances played roles in their victories. This is nonsense; the act of surviving the NBA postseason marathon and its opponents is the definition of what makes a champion.

The injuries have robbed fans of better quality in this series to this point. But the Celtics have earned the lead. They have exhausted their opponent. They have had more when it mattered.

Boston's path to this moment has not been the idyllic storybook tale -- at least not yet -- but it has been awfully effective just the same.

"The mental stress and strain we put on some teams with our defense has worked and carried us through the playoffs at times," Udoka said. "You saw in the Brooklyn [Nets] series, guys started to wear down. Game 7, [Giannis] Antetokounmpo slowed down some. But having all those bodies to continue to throw at people wears down on them."