This is the first installment of a preseason series in which ESPN fantasy experts debate a pair of players who have similar fantasy values and/or average draft positions. First up, Greg Rosenstein and Tom Carpenter battle over a fantasy legend in the Cleveland Cavaliers' LeBron James and Milwaukee Bucks upstart Giannis Antetokounmpo.

Carpenter on why Antetokounmpo should go ahead of James

Let's just get this out in the open: I have a fantasy crush on the 21-year-old Antetokounmpo. Enough so that I can type his name quickly and say his name without tripping over my tongue, like Stacey King.

I think his ultimate ceiling is comparable to Kevin Garnett in his Big Ticket prime. I always did everything possible back in the day to land KG, and The Greek Freak will be no different.

LeBron has a safe floor on a per-game basis, but his ceiling is shrinking each year, as he focuses on staying healthy and preparing for another deep playoff run, while leaning more on his teammates during the regular season.

As for The Greek Freak, I'll grant that his floor could be dangerous for a first-round pick, but let's check out that sky-high ceiling.

Consider his post-All-Star break numbers last season: 18.8 PPG, 7.2 APG, 8.6 RPG, 1.4 SPG, 1.9 BPG, 50.9 FG%.

Now consider KG's numbers in his third season at age 21: 18.5 PPG, 4.2 APG, 9.6 RPG, 1.7 SPG, 1.8 BPG, 49.1 FG%.

... and LeBron in his third season, at age 22: 31.4 PPG, 6.6 APG, 7.0 RPG, 1.6 SPG, 0.8 BPG, 48.0 FG%.

Are you giddy for Giannis yet?

You can see what the youngster has in common with those fantasy legends is versatility -- the ability to score efficiently, dish, hit the glass and play defense. The key to Antetokounmpo's ceiling this season will be field goal attempts per game. Garnett averaged 15.8 FGA per game during his third campaign, while James averaged 23.1 FGA per game.

Twenty-three points per game is a pipe dream for Antetokounmpo; even I can't hope for that, since the Bucks ranked 22nd in pace last season. On the other hand, he averaged 14.1 FGA per game after the break, so KG's 16-plus is well within reach and could easily be passed, since last season's Bucks scoring leader Khris Middleton is out for most of the season.

Just as importantly, he is going to be the de facto point guard, since this team doesn't have anyone worthy of running an offense -- no offense to Matthew Dellavedova or Michael Carter-Williams -- so he is going to have the rock in his hands constantly. Serving in that role after the All-Star break last season, he racked up five triple-doubles (in 26 games), compared to Russell Westbrook's 10 and LeBron's two.

Antetokounmpo stands a Garnett-esque 6-foot-11, 222 pounds, is able to play all five positions, and will be a matchup nightmare for every team he faces. Furthermore, that versatility helps fantasy teams, because he is eligible at SG, SF and PF, unlike James, who slots in at only SF and PF.

And when you are fighting for a fantasy championship in March and April, James will be skipping random games, as he focuses on another NBA championship. Last season, he sat out four games in the last month, which means he stole 101.2 points, 27.2 dimes and 29.6 boards from you in roto games ... and one big box score per week four times in head-to-head playoffs.

We should fully expect Antetokounmpo to continue playing big minutes in every game down the stretch this season, because he is young and has missed a total of three games the past two seasons.

When it comes to fantasy drafts, I prefer targeting young players who are at the start of their career arcs with the hope they will explode and outpace their draft spots. So be bold, take Antetokounmpo in the middle of the first round over James and enjoy the fantasy crush all season long.

LeBron James' elite defensive ability was shown during last season's NBA Finals matchup with Golden State. Ken Blaze-USA TODAY Sports

Rosenstein on why James should go ahead of Antetokounmpo

Don't get me wrong, I love The Greek Freak. Milwaukee's fourth-year do-everything small forward, is one of the most exciting players in the NBA. At 6-foot-11 with the ability to compete on both ends of the court at nearly every position, he's among the most unique individual talents in the sport.

But he's no LeBron.

The Cavaliers small forward/power forward has three more NBA titles, 10 more playoff appearances, 12 more All-Star games, four more regular season MVPs... I could go on and on about his career accomplishments. He's a guaranteed Hall of Famer and will likely finish as one of the top five players of all-time.

However when dealing with just this season, I'd still side with the King.

Part of the reason, in fact, is consistency. I know exactly what I'm going to get from him. If you take out his rookie season in 2003-04 -- still a very strong year at age 20 -- he has never averaged less than 25 points, six rebounds, six assists or 1.4 steals a game in 12 years. He's also never shot under 69 percent from the line, 30 percent from 3-point range or 47 percent from the field. Again, this is when he's at his worst, and oftentimes he's much higher in these respective categories.

Is there any real reason to think any of that will change in 2016-17? Antetokounmpo, in contrast, had a career-year last season, averaging 16.9 points, 7.7 rebounds, 4.3 assists and 1.2 steals a contest. That's cute. It would also constitute as LeBron's worst season ever.

I think the biggest argument you can make for the Greek Freak is his versatility. If you draft him early, you can plug him in at one of three positions. That's a big deal. But it also means he's going to be handling the ball more outside the arc running the offense and is likely to be further away from the rim more than ever before. This means a worse shooting percentage. According to NBAMiner.com, Antetokounmpo shot 60.5 percent from less than eight feet (66.37 percent of his shots) and only 29.7 from more than eight feet (33.63 percent of his shots). His attempts from further away are likely to increase in this new role.

The loss of Khris Middleton should increase Antetokounmpo's usage percentage, but keep in mind Middleton was one of the only above-average 3-point shooters on the team. Spacing will be an issue for the Bucks in 2016-17, forcing players like Giannis to take bad shots.

LeBron, once again, will be LeBron. Few players in the game can match his combination of scoring, distributing, and rebounding. While Giannis is an extremely promising player, at this point we're still just hoping he takes that next step. James took that step more than a decade ago and has remained at that elite level, and I'd take that any day of the week.