6'0, 215 pounds
The first thing that you'll notice when you watch Ajayi is his outstanding balance. He's able to absorb contact and keep his feet underneath him with ease. Arm tacklers aren't going get much done against him. He can bounce off of first contact without flinching. The snap below is one of the many examples of Ajayi's balance. He makes contact with three defenders before finally going down.
Ajayi is fantastic coming out of the backfield. He shows soft hands when catching the football and can turn up the field nicely. He's better in the open field than you think. Ajayi isn't a "scat-back" by any means, but he possesses deceptive agility. He keeps his speed in and out of cuts which makes him very effective in the open field.
His vision is fantastic. He's light on his feet and can cut up field quickly. He lacks some acceleration, but he makes up for it with smooth, seamless cuts. The play below shows what Ajayi offers. He diagnoses the defense and finds the alley. From here you can see what Ajayi offers in the open field.
Ball security is a bit of an issue. He fumbled 12 times during his entire career, but 7 of those happened in 2014 alone. However, he did handle nearly 350 carries, so I don't believe it's a huge deal. Just something to keep in mind.
Ajayi has an average burst at best. He's more of a rhythm runner than anything. I wouldn't expect him to lay down a blazing 40 time either. He's lacking in the power department as well. He looks bigger than his listed weight, but appears to have a skinny, weak lower half. None of these things are nessecities for the position, but it will most likely force him down a few draft boards.
Jay Ajayi is Arian Foster 2.0. Like Foster, Ajayi would thrive in a zone blocking scheme. His vision and ability to make smooth cuts without losing speed is what will make him successful in the NFL. He's a complete player that won't have to come off of the field in any situation.