Here's my take on Lewis, which might not make sense, but it does to me:
Yes, he finished as RB6 last year.
And yes, he had over 1300 rushing yards and 9 TDs.
However, those #s did not come with any sort of consistency.
He averaged 87 rushing yards a game. So if you break that up in a +/- 15 form, you have:
8 games where he rushed for 72 yards or fewer
2 games where he rushed for 73-101
5 games where he rushed for 102 or more
If you go another 15 yards out (to really see if he hits the extremes):
5 games with 57 or fewer yards (plus another 3 right near there: 64, 61, 62)
5 games with over 117 yards
To me, this means each week he is hit or miss. You never know what you are going to get.
Take someone like Jacobs, who FBG has 5 spots lower was a bit more consistent.
Jacobs rushing #s: 11 games, 1011 yards. That's 92 yds/game.
If you do the same thing with the +/- 15 yards:
4 games where he rushed for 77 or fewer
3 games where he rushed for 78-106
4 games where he rushed for 107 or more
That means Jacobs rushed for 78 or more in 7 of his 11 games.
While Lewis hit his mark (which was less) of 73 or more in 7 of his 15 games. Less than 50% of the time.
Now let's look at ADP according to myfantasyleague. They have Lewis at 28th overall; Jacobs at 39th.
So according to them, in a 12 team league, Lewis is a 3rd round pick, while Jacobs is a 4th round pick.
Let's look at one more source just to confirm. According to the FBG expert overall re-draft rankings, they have Lewis at 18th; and Jacobs at 29th. So they have Lewis as a 2nd round pick; while Jacobs is at a 3rd round pick.
Either way, whether it is 3rd round versus 4th round; or 2nd versus 3rd, both sources confirm that Lewis will cost you a full round higher. And while there is a very good chance Lewis will finish better than Jacobs, consider two things:
a) those #s will not come in a consistent pattern;
b) in the 2nd round, you can take a WR like Owens, Edwards, Fitzgerald; in the 3rd it would be Holt, Plax.
So even if Lewis is better than Jacobs, which combination is better:
Fitzgerald/Jacobs or Lewis/Plaxico