It's still early in the season, but the race for the NBA Rookie of the Year award is already heating up in a big way.

There are so many talented rookies in this year's class that the top two overall picks in the 2017 NBA Draft -- Markelle Fultz and Lonzo Ball, respectively -- didn't even make the top five.

It's a good time to be an NBA fan, as there are plenty of bright young stars to root for, but only one can take home the ROY trophy.

There is still a lot of basketball left to be played, but five rookies have stood out above the rest so far this season.

Through approximately 20 games for most teams, here are the five rookies who have made the biggest impact for their teams already this year:

5. Dennis Smith Jr., PG, Dallas Mavericks

No, the Mavericks aren't having a great season. In fact, through 20 games, they have the worst record in the Western Conference at 5-15.

However, the Mavs were never going to compete for a playoff spot this year, so developing Smith is the main focus of the 2017-18 season, and so far, it's going quite well.

The Mavericks appear to have their point guard of the future in Smith, who is one of the most-explosive rookies on this list. He's averaging 14.3 points, 4.3 assists and 4.1 rebounds per night for the Mavericks through 18 games.

4. Kyle Kuzma, F, Los Angeles Lakers

Heading into the season, many Laker fans thought No. 2 overall pick Lonzo Ball would be the player on this list, but while Ball has struggled, former Utah star Kyle Kuzma has stood out.

The No. 27 overall pick has developed into quite a scorer, averaging 16.8 points and 6.3 rebounds per game so far.

He certainly benefits from receiving passes from Ball, but for now, Kuzma is the Lakers' rookie with the better numbers and is every bit deserving of a spot on this list.

3. Donovan Mitchell, PG, Utah Jazz

The Jazz have struggled this season, but that's more due to the fact that star center Rudy Gobert is out than it is about anything Mitchell has done.

When the Jazz got Mitchell at the No. 13 spot of the draft, it was widely considered a great pick, and that pick has certainly paid off.

Mitchell has been a key player for the Utah offense, averaging 14.8 points, 3.3 rebounds, 3.2 assists and 1.4 steals per game. As his minutes continue to increase, so does his production.

2. Jayson Tatum, F, Boston Celtics

Many questioned GM Danny Ainge when he traded the No. 1 overall pick to the Philadelphia 76ers and moved down to No. 3, where he selected Tatum.

However, Tatum has been one of the best rookies of his class, and if it weren't for the unusual circumstances surrounding the No. 1 player on this list, Tatum would have a good chance of winning the Rookie of the Year award.

Tatum has started all 21 games for the Celtics so far this season and is averaging 13.9 points and 5.5 rebounds for a team that has gotten off to a scorching-hot 18-3 start.

1. Ben Simmons, G/F, Philadelphia 76ers

Simmons was the No. 1 overall pick of the 2016 NBA Draft, but missed all of last year with an injury. However, it's safe to say he's been well worth the wait for the Sixers.

Simmons can do it all on the court, serving as the Sixers' point forward and leading the team to a surprising 11-7 record through 18 games.

The star rookie is averaging impressive totals of 18.5 points, 9.1 rebounds and 7.7 assists already this season and is playing more like an MVP, not a Rookie of the Year. The award, right now, is his, but he'll need to stay healthy to take home the hardware.