The best candidates for NFL Rookie of the Year awards aren't just about who is the best player. A confluence of factors -- from raw talent, to the opportunity to start immediately, to being surrounded by the right cast of teammates -- is required for one rookie to rise above all others. Here is a look at five strong po sibilities for the 2015 NFL Defensive Rookie of the Year award. Leonard Williams, DL, New York JetsWho could argue with the most-talented and pro-ready player in the entire draft as an ROY Freddie Swain Jersey candidate? The addition of Williams to a defensive line that already includes and is nothing short of fearsome. And the presence of the veterans will go a long way toward keeping Williams in the one-on-one situations that he dominated routinely at the college level. The last two defensive ROYs have been defensive linemen, including Richardson in 2013 -- why not another Jet at the same position?Randy Gregory, LB, Dallas CowboysThe last time a defensive ROY was picked later than Gregory was (No. Tre Flowers Jersey 60 overall) was , whom the drafted . Still, Gregory's slip in the draft had more to do with character concerns than what he can do on the field. He just might prove to be the best pa s rusher in the entire draft, and if that's the case he's a major threat for the honor. He's in a big market playing for "America's team," so there will be no shortage of attention on him. If he delivers, he'll be in the conversation Rashaad Penny Jersey .Marcus Peters, CB, Kansas City ChiefsThink Peters won't get tested as a rookie? He's got and in his division, along with an up-and-comer in , who has added to his arsenal. Out of division, he'll get a look at , and . Whether he pa ses those tests or just gets picked on as an easy target remains to be seen, but there shouldn't be any shortage of balls thrown his way.Bud Dupree, LB, Pittsburgh SteelersThe were desperate for a fresh face on the edge of its pa s rush, and got just that in Dupree, who brings more size than most of the top pa s rushers in the draft at 265 pounds. New defensive coordinator Keith Butler worked under Dick LeBeau, and should have no problem carrying forward LeBeau's ability to put a pa s rusher in a position for succe s. If Dupree doesn't win the ROY award, expect him to be a C.J. Prosise Jersey serious contender for it.Landon Collins, DB, New York GiantsYou know an NFL rookie is special when it looked like he was playing with kids in college, then with old men in the NFL. Collins' physicality at Alabama certainly gave the former impre sion, and the latter could be coming. The moved up seven spots and gave up a fourth-round pick to make Collins the first pick of - Tyler Ott Jersey - he'll get every chance to be a starter from Day 1. Collins is more of a hitter than a ball hawk, but has a knack for making big plays one way or another. If things go well for the ' defense, he'll have a significant hand in it.Follow Chase Goodbread on Twitter .