Fantasy owners are already falling in love with Johnny Manziel's potential, but given history, he's more than likely going to disappoint.

Iâ€™m not one to bash Johnny Manzielâ€™s off-the-field antics, acting as though I know what it's like to be under a tremendously bright spotlight. What I will talk down, however, is this idea that Johnny Manziel â€“ a quarterback who hasnâ€™t even been named starter for his football team â€“ is already a relevant fantasy asset.

Weâ€™re all aware that quarterback scoring favors running quarterbacks, and we even dubbed this notion â€œThe Konami Codeâ€ here at numberFire a season ago. And hey, Johnny Football can sure tote the rock. But Iâ€™m still not buying him Year 1. Iâ€™m not buying for a lot of reasons.

Cam and RGIII Comparisons Are Whack

Folks in the Manziel camp point to Cam Newton and Robert Griffin IIIâ€™s rookie campaigns as reason to believe in a high fantasy football ceiling for the Brownsâ€™ passer. This is especially true with RGIII, as his rookie year offensive coordinator, Kyle Shanahan, is the one Manziel will be coached by in Cleveland.

For reference, here are the rushing statistics from those two quarterbacks during their rookie seasons:

Player Attempts Yards TDs Rushing NEP Rushing NEP Rank Robert Griffin III 120 815 7 59.29 2nd Cam Newton 126 706 14 50.28 5th

The Rushing Net Expected Points (NEP) numbers above tell us the amount of points the two quarterbacks added for their respective teams over the course of their rookie season on the ground. The rank listed isnâ€™t the ranking for that particular season, but the ranking for those two seasons in the context of every quarterback campaign since the year 2000.

In other words, RGIIIâ€™s first year in the NFL was the second-best rushing one from a quarterback that weâ€™ve seen over the last 14 years, while Camâ€™s ranked fifth. Naturally, Michael Vick owns the other three top-five seasons.

Why show this? Well, considering 85 different signal-callers have run the ball at least 50 times in a single season since 2000, in order for Manziel to be as effective on the ground as RGIII and Cam, heâ€™d need to rank in at least the 95th percentile as a running quarterback (assuming a 50-carry baseline). Can he? Sure. Is it probable? Not at all, especially when you consider the top 10 quarterbacks in Rushing NEP since 2000 consist of only four names (Donovan McNabb included).

If we take the baseline raw rushing statistics from Cam and RGIII - letâ€™s say 700 yards and 7 touchdowns â€“ we find that these two passers, within the context of all quarterbacks in NFL history, were indeed extraordinary during their rookie seasons.

Player Year Att Yds TD Spec Sanders 1947 231 1432 18 Spec Sanders 1948 169 759 9 Bobby Douglass 1972 141 968 8 Cam Newton 2012 127 741 8 Cam Newton 2011 126 706 14 Dutch Clark 1934 123 763 8 Robert Griffin III 2012 120 815 7 Michael Vick 2002 113 777 8

The only other recent quarterback to do what Manzielâ€™s supposed ceiling is would be Michael Vick in 2002. In fact, Michael Vick, one of the best runners the league has ever seen, has posted 700 rushing yards and 7 rushing touchdowns just once in his career.

Even if you put this in context of fantasy points via the ground, Manzielâ€™s odds are massively stacked against him. The 700-yard, 7-touchdown total equates to 112 standard fantasy points, or 7 rushing fantasy points per game (let that sink in for a second).

What does this mean? Well, over the course of Michael Vickâ€™s career, heâ€™s averaged 6.26 rushing fantasy points per game. Cam Newton has averaged 7.7, while RGIII â€“ albeit, with an injured knee in 2013 â€“ has averaged 6.16.

And this only includes rushing metrics. If we relate back to the original comparisons with Robert Griffin III and Cam Newton, we have to recognize that both of these quarterbacks were incredibly gifted passers through the air during their respective rookie campaigns.

Over the course of NFL history, 48 quarterbacks have posted at least 2,000 passing yards during their rookie seasons. Admittedly, most of the players listed atop the list have been recent ones, like Andrew Luck and Peyton Manning.

But number two on this list is Cam Newton. Number 11 on this list is Robert Griffin III.

When filtering rookie quarterbacks and ranking them in terms of touchdown passes, youâ€™d find that 11 different first-year passers finished with 20 or more throwing scores. Yes, only 11. Over the course of NFL history.

And you know who made the list? Robert Griffin III and Cam Newton, of course.

Cam Newton and Robert Griffin III were not just effective in fantasy football during their rookie campaigns because of what they could do with their legs. Both were prolific through the air as well. And if weâ€™re now projecting a ceiling for a player to be as historic as we are with Johnny Manziel, then I guess we should begin to say that Teddy Bridgewater has a 4,300-yard ceiling similar to Andrew Luck because Norv Turner is his offensive coordinator, or that Blake Bortles has the potential to throw 26 touchdowns similar to Peyton Manningâ€™s 1998 rookie record.

No? Well then stop with the ridiculous ceiling for Johnny Manziel, and look at whatâ€™s realistic.

Realistic Numbers for Manziel

Prior to the NFL Draft, numberFire CEO, Nik Bonaddio, put together a piece on Manziel that showed the kind of potential the star has at the NFL level based on his measurables. The algorithm used in the study was called READ, and it looked at players who match up to Manziel, giving Johnny Football a list of guys who rank similarly based on their overall body of work.

Manzielâ€™s READ comparables werenâ€™t pretty, but the top one, Alex Smith, was an interesting one. Smith stands at 6â€™4â€™â€™, and is a bigger-bodied quarterback than Manziel. But many of his combine measurables stack up similarly, including a 4.7 40-yard dash, .02 seconds slower than Manzielâ€™s.

Smith wasnâ€™t a dazzler on the field with his legs in college like Manziel was, mostly because Manzielâ€™s rushing numbers at Texas A&M were downright dirty. But in Kansas City last year, the once laughed at quarterback actually posted really underrated rushing statistics, adding 49.1 fantasy points to his total via the ground game, good for over 3 points per week.

If Manziel gets the starting gig in Cleveland, Iâ€™d expect him to outplay those numbers, especially considering heâ€™d probably run the ball more than 76 times. The interesting part here, however, is that Alex Smith isnâ€™t even being selected in fantasy drafts according to FantasyFootballCalculator.com, while Johnny Manziel is being drafted as the first pick in Round 12.

Whatâ€™s also fascinating relates back to the point about Cam Newton and Robert Griffin IIIâ€™s passing numbers. We shouldnâ€™t expect effectiveness from Manziel through the air in Year 1 given the upcoming suspension of Josh Gordon and a bunch of declining veterans at wide receiver. Jordan Cameron is nice, but the wide receivers in Cleveland look about as attractive as a Desmond Bryantâ€™s mugshot.

Letâ€™s pretend, for a moment, that Johnny Manziel rushes for 600 yards and 5 touchdowns during this upcoming season, a line Iâ€™d assume people would believe as a very reasonable outcome for the rookie. After all, only 20 quarterback seasons in the history of the NFL have ever seen this type of production on the ground.

If we were to also believe that Alex Smith posts another season with 253.22 fantasy points, then this means, in order to match Alex Smith, Johnny Manziel would have to score 163.22 points with his arm.

There are plenty of ways to get to 163.22 points through the air. One way would be to throw for 3,000 yards, 15 touchdowns and 8 interceptions.

In NFL history, nine quarterbacks have thrown for 3,000 yards and 15 touchdowns as a rookie. Of these quarterbacks, eight have thrown at least 10 interceptions.

This is a rather arbitrary, simple exercise, but what I hope it shows is how many things need to go right, according to history, for Johnny Manziel to be a legitimate QB1 this season. Remember, the statistics above arenâ€™t even top-12 quarterback numbers, either. Alex Smith ranked 13th at the position a season ago, meaning Manziel would have to outperform these historic numbers in order to be a weekly starter.

If Iâ€™m drafting a fantasy team tomorrow, Iâ€™m taking Alex Smith over Johnny Manziel.

Whereâ€™s the Correct Cost?

The reason for optimism for Johnny Manziel is certainly warranted. Few quarterbacks enter the NFL with such a great rushing pedigree, and having Manziel shares in fantasy football would make for a fun ride.

But hereâ€™s the deal. Johnny Manziel isnâ€™t even the starting quarterback in Cleveland right now, and his average draft position sits at the beginning of Round 12. At that point in the draft, I understand that a fantasy owner is strictly drafting for upside, and because quarterback is so replaceable, throwing a dart at Manziel isnâ€™t a big deal.

If and when heâ€™s named starter? Watch out.

We saw, given history, how difficult itâ€™s going to be for Johnny Manziel to become a high-end QB2 in fantasy football (Alex Smith numbers) in Year 1. If he moves into the 10th round, heâ€™s now being selected as just that. And it shouldnâ€™t surprise anyone to see that happen if Manziel has a solid preseason and is named starter over Brian Hoyer to begin the season.

The thing is, the quarterback landscape in fantasy football is even more competitive in the mid- and late-rounds than it was when Cam Newton and Robert Griffin III were entering the league. The opportunity cost then is not the same as the opportunity cost now.

If Manzielâ€™s cost begins to move to the single-digit rounds, youâ€™re not just betting against the odds given historical rookie quarterback production, but youâ€™re now forgoing locks at the position. You're missing out on players with just as much upside, like Jay Cutler and Philip Rivers.

Manziel is flashy, and heâ€™s going to be entertaining to watch. And I wouldnâ€™t put it past him to exceed my pretty reasonable expectations. But even if he does, itâ€™s going to be difficult for him to be a fantasy football value on draft day.