The NBA playoffs are here with four first-round games taking place on Saturday and Sunday.

In the East, all eyes will be on the Boston Celtics vs. Brooklyn Nets series as Kevin Durant and Kyrie Irving look to upset the No. 2 seed Celtics, who are without injured center Robert Williams III, in what should be a competitive series.

Out West, injuries could dictate the teams that advance. Dallas Mavericks star Luka Doncic will miss Saturday's Game 1 against the Utah Jazz because of a strained left calf, according to ESPN's Adrian Wojnarowski and Tim MacMahon. And Golden State Warriors guard Stephen Curry is listed as probable for Game 1 against the Denver Nuggets after missing the last 12 games of the regular season with a left foot injury.

Which returning player could have the biggest impact? Which higher seed can least afford to lose Game 1 this weekend? Our NBA experts break down the top first-round storylines.

MORE: What to know for the NBA postseason | Schedules

1. Which first-round series stands to be the most competitive?

Kevin Pelton: Boston and Brooklyn. As I laid out in my series preview, the Nets have been much better than their overall record with Kevin Durant healthy and Kyrie Irving available alongside him, while the Celtics aren't the same juggernaut without injured center Robert Williams III. As a result, these teams look surprisingly even for the No. 2 and No. 7 seeds.

Tim Bontemps: Many will probably say Nets-Celtics, given the star power involved, but I'm going to go with another Eastern Conference series: Philadelphia-Toronto. The 76ers have the best player in the series by a significant amount in Joel Embiid. But Toronto should have a coaching advantage, Philadelphia won't have Matisse Thybulle for all three games in Toronto, and the Raptors have the perfect assortment of long, athletic players to both take advantage of Philadelphia's lack of athleticism and make James Harden's life extremely difficult. Embiid should be enough to power Philadelphia through and win this series. But this should be a very difficult test -- one that easily could go seven games -- and could send Philly home far earlier than it expects.

Kevin Arnovitz: Dallas-Utah. Both 4-5 matchups have strong seven-game potential, but the Mavericks and Jazz should be really competitive. It's been a while since Utah played a sustained stretch of dominant basketball, but the Jazz are still the league's top-ranked offense. Meanwhile, Dallas has been one of the best stories of 2022. When healthy, Luka is Luka. Spencer Dinwiddie has added some juice the team desperately needed from the perimeter, and the defense -- traditionally a weakness -- has been strong all season. Both of the teams have been disappointments in recent postseasons ... and one will be so again when this series is over.

Ramona Shelburne: Even without Luka Doncic missing Game 1, I thought the Mavericks-Jazz series was going to be a tight one. I know a lot of people are down on the Jazz because of their past playoff failures, but I've always felt like they have the ability to put it together one of these years if they hit a few breaks.

Jamal Collier: Boston-Brooklyn. I don't think a team with Durant and Irving is going to go out quietly. This feels like a seven-game series with a chance for several games to come down to the wire, and those are two dangerous players to try to outdo in clutch performances. Ultimately, it's hard for me to see the Nets playing or defending at a high enough level for four out of seven games to pull this series off, but it's going to be fun to watch.

2. Which injured player's return could have the biggest impact on the first round?

Pelton: Doncic coming back from a calf strain. Although Stephen Curry is at least as valuable to his team, Curry's timetable is clearer. We have no idea right now whether Doncic can get back on the court for Game 2 after our ESPN colleague Adrian Wojnarowski reported he'll miss at least the first game of the Mavericks' series against the Jazz. The speed of his recovery will go a long way toward determining the outcome of that series.

Bontemps: I thought Dallas was the biggest threat to Phoenix in the Western Conference before Doncic hurt his calf in the Mavericks' regular-season finale. Now, Utah is likely the favorite to advance, as we have no idea how much Doncic will be able to play -- or how effective he will be. What looked like a chance for the young superstar to make a deep postseason run could now be over before it starts.

Arnovitz: Doncic is the engine, fuel and torque of the Mavericks' offense, and his condition is more important to his team than any single player in the West. Dinwiddie and Jalen Brunson can run a quality pick-and-roll attack, but neither has the creativity to turn every guy on the floor into a threat. The good news for Dallas is that its defense has been stingy and, given Doncic's deficiencies on that end of the floor, that shouldn't change.

Collier: Doncic. I don't think there's a single team in the NBA whose success is tied to one player as much as the Mavericks' is to Doncic. If he doesn't play or isn't 100 percent I don't think Dallas can advance in this series.

Shelburne: The Warriors can win a few games without Curry, but they really aren't the Warriors without Curry, are they? It'll take him a few games to get it rolling, but once he does, he completely changes the dynamics of that team.

3. Who is your pick for the breakout player of the playoffs?

Pelton: Bruce Brown, who has been playing at a high level for the past two months. Brown averaged 14.7 PPG, 5.9 RPG and 3.7 APG after the All-Star break, finding an ideal role supporting Durant and Irving on offense while serving as the Nets' top perimeter defender. He has flirted with triple-doubles in two of Brooklyn's past three games and the Nets need him to play at this level to advance deep in the playoffs from the play-in.

Bontemps: Jaren Jackson Jr. Obviously when everyone thinks of the Memphis Grizzlies, the first person they think of is Ja Morant -- and deservedly so. But Jackson has taken a massive leap forward this season defensively, launching himself into All-Defense and Defensive Player of the Year conversations. With the Grizzlies having a chance to make a deep playoff run for the first time, Jackson will have the chance to show the world why he and Morant are such an electrifying one-two punch in Memphis.

Arnovitz: For two seasons, Memphis Grizzlies guard Desmond Bane has established himself as a steal at No. 30 in the 2020 draft with his 43.5% career 3-point percentage. But Bane also has a floor game that's improving, and the strength to impact the game on both ends. Minnesota surrenders a heavy volume of 3-point attempts and will be devoting a ton of attention to Morant, which gives Bane an opportunity to be a lethal second-side threat for the Grizzlies.

Shelburne: Does Morant count? Because I think he's going to surpass everyone's already high expectations for him and the Grizzlies. I had an executive I trust tell me a few months ago that Memphis could be the best team in the league. The more I think about it, the more I'm starting to agree with him.

Collier: Anthony Edwards. No player is going to benefit more from his first exposure on the national stage, both on and off the court. Even if his team can't pull off the upset, Edwards will be the player everyone is talking about after this series.

4. Which higher seed can least afford to lose Game 1?

Pelton: Philadelphia. The Sixers are in an unusual spot because they already know they'll be short-handed for road games in Toronto due to Thybulle's vaccination status. Losing Game 1 would force Philly to win at least one road game and put more pressure on the team's other defensive options on the wing.

Bontemps: Philadelphia, both because Thybulle won't be available in road games and to set a good tone for this series by getting off to a good start. But this could also apply to Dallas, with Doncic's uncertain health, and the Golden State Warriors, due to Curry's injury situation, as well.

Arnovitz: The Philadelphia 76ers. Anyone who has spent considerable time in Scotiabank Arena in the springtime knows that the Raptors and their home crowd extend zero hospitality to visitors. Those road games in Toronto will be even more treacherous for the Sixers without Thybulle. On top of that, the Sixers lost some of their depth at the deadline, while the Raptors' OG Anunoby, one of their best two-way threats, just returned.

Shelburne: Philadelphia was always gonna have a tough matchup with Toronto due to the Raptors' length and depth. Now the Sixers have to play without Thybulle in Toronto, making it even more important to hold serve at home.

Collier: Philly. Game 1 overreactions are an underrated great part of the playoffs, and I don't imagine everyone will take it in stride if the Sixers lay an egg at home to start the series. Especially considering they'll be playing short-handed in Toronto.

5. What's your bold prediction for the first round?

Pelton: Having scored 50 points in Game 3 of last year's first-round matchup against Brooklyn, Jayson Tatum will break the Celtics' playoff single-game franchise record held by John Havlicek by scoring at least 55 against the Nets.

Bontemps: I'll say it's that the Atlanta Hawks get two games off the Miami Heat in the first round, and that series is more competitive than the usual 1-8 bloodbath (which is what the Western Conference version will be). Atlanta has had a strange season, but it's a very talented team with playoff experience from last year's run and a player in Trae Young who has proved he can win a playoff game by himself.

Arnovitz: Denver takes Golden State to seven games. Curry dictates the Warriors' fortunes -- full stop. If he's limited, whether in minutes or mobility, they're far, far easier to defend. The Nuggets feature the best offensive player in the series, and know how to create high-percentage looks in the half court, which means the Warriors' vaunted D will have to play at its full potential. Either way, it's going to be nip and tuck.

Shelburne: How bold is it to suggest the second-seeded team in the East wins its first-round playoff matchup? Because I think Boston is going to beat the star-crossed Nets. I know how great Durant and Irving are, but they are really being asked to do a lot, and at some point that wears you down. Especially against a great defensive team like Boston.

Collier: Ben Simmons will make his season debut. The fact that there continues to be smoke about a possible return makes me feel like, eventually, there will be fire. It would be bizarre and a fitting chapter to this never-ending saga: Simmons returns to the court during the playoffs for a home game in Brooklyn, one year after playing in his last game.