LSU's Leonard Fournette is the best running-back prospect in the 2017 NFL draft, a special player who could step in on Day 1 and play all three downs. But he won't be an option for every team.
Running backs have been devalued in the top half of the first round in recent years, and they're not being picked as high as they used to be. Last year, only one back (Ezekiel Elliott) was taken in the first round. In 2015, there were two (Todd Gurley and Melvin Gordon). In 2014 and 2013, there were none.
Some of the backs taken in the top 10 recently haven't panned out. Trent Richardson (No. 3 in 2012) and C.J. Spiller (No. 9 in 2010) are out of the league, and Darren McFadden (No. 4 in 2008) signed a cheap deal with the Cowboys after the Raiders moved on.
That makes teams wary of taking a back in the top 10, even if it's a guy as talented as Fournette. Here are the three best fits for Fournette as I see things right now:

Cleveland Browns
Projected pick: No. 1
The winless Browns need a lot of things, and I'm in favor of them taking the best player available, who for them could very well be Fournette. I have him No. 4 on my Big Board, but it's not out of the question that Cleveland could have him No. 1, like Todd McShay. Fournette is that good, and Cleveland could absolutely use a big-time running back with rare size (6-foot-1, 235 pounds), speed and power. The Browns are at the beginning stages of their rebuild, and they could follow Dallas' plan of building up their offensive line and picking a spectacular running back. They already have left tackle Joe Thomas and guard Joel Bitonio as building blocks along the line, and Fournette would be a great addition. Yes, the quarterback question lingers over Cleveland, but remember, this isn't going to be a draft to take a quarterback at No. 1. I don't see a top-tier signal-caller in this class.

Carolina Panthers
Projected pick: No. 7
This is where McShay has Fournette in his first mock draft, and I think it'd be a great fit for both sides. The Panthers once spent two first-round picks on running backs in Jonathan Stewart and DeAngelo Williams, but Williams moved on after the 2014 season, and they could part ways with the 29-year-old Stewart, who's averaging only 3.6 yards per carry in an injury-plagued 2016 this offseason. That would leave a void in the backfield in Carolina, where Fournette could form a dynamic power-rushing attack with Cam Newton. Could you imagine defenses taking on Newton and Fournette in the read-option?

Detroit Lions
Projected pick: 24
Now, this would require a trade up, as I don't think Fournette slips out of the top 10. If he does drop past the top seven picks, the Lions could be enticed to give up a few picks and move up for a game-changing talent. Detroit has a great offense, but that's because of Matthew Stafford and the passing game. The Lions' running game is one of the worst in the league, and their top back, Theo Riddick, is a much better pass-catcher than between-the-tackles runner. Former second-round pick Ameer Abdullah is dealing with a serious foot injury and has only 698 rushing yards and two touchdowns in two seasons. Fournette would make that offense more complete and take some pressure off Stafford.