Im high on him this year, in the mid-3rd or later. You people talking about taking him in the early to mid-2nd is kind of crazy. Now maybe he's gone by your 3rd pick, but Id say that's 50/50 at worst considering the glut of RBs and WRs in that range. SJax is a value guy just for that reason, he always seems to slide in drafts. No need to use a 2nd rounder on him. If anything, go with an upside RB pick like DMC, MJD, or Murray with your 1st or 2nd pick then go after SJax in the 3rd to minimize the risk with your first RB.
I don't know about anybody else, but I've done quite a bit of mocking (from the 9 spot in a 12 team) and while I am contemplate Sjax for my second round pick in my real draft, I don't think I've seen him last past the second round/early 3rd at the latest. If anything and in my opinion, he presents great value if he makes it to the 3rd round AS a #2 RB on your squad or #1 RB if you grabbed Megatron or a QB with your first pick..
You say "considering the glut of RB's"...and there's not this year. You comment on the likes of DMC and Murray both of whom ARE being drafted before Sjax and if you draft either of those guys, if you don't take Sjax with your second overall pick, you are chances of being able to do so in the third or later as you suggest are basically ZERO.
He is an undisputed #1 RB on a team that is NOT rbbc. New coach, new scheme + he catches the ball.