Though the NFL draft remains a very inexact science for teams trying to bolster their rosters, the perception is that players taken in rounds 1 through 3 should be able to step in and compete for jobs immediately. For players selected on the draft's third day, which consists of rounds 4 through 7 -- of for those signed to free-agent deals after the draft is over -- there is usually a tough road ahead.
And yet, inevitably, a steady collection of those later-round prospects wind up with starting jobs when the regular seasons begins.
That is true again in 2013, with the following players all closing in on critical roles with their new teams:
• David Bakhtiari, OT, Packers (Round 4): No secret here. Bakhtiari took over Green Bay's left tackle job after Bryan Bulaga suffered a season-ending knee injury. Audibles' Doug Farrar took a closer look at Bakhtiari's potential earlier this month.
• Dion Sims, TE, Dolphins (Round 4): With Dustin Keller out for the season -- and maybe longer -- after suffering a gruesome knee injury, Sims has a shot to beat out Charles Clay (sixth round, 2011) and Michael Egnew (third round, '12) for the starting job. The 6-foot-4, 265-pound Sims had one grab for 18 yards in a 17-16 loss to the Buccaneers on Saturday, and should be part of Miami's offensive plans going forward.
• Kenny Stills, WR, Saints (Round 5): Stills showed his stuff in a 31-23 victory over the Texans on national TV on Sunday, hauling in a 40-yard grab in the second quarter, and then smoking cornerback Jonathan Joseph for a 14-yard touchdown four plays later. The Oklahoma product will be New Orleans' No. 3 receiver, with Joe Morgan out for the year with a knee injury.
• Earl Wolff, S, Eagles (Round 5): The preseason has not been particularly kind to the rookie, who was burned on Jordan Todman's long TD run in a 31-24 win over the Jaguars on Saturday, but Wolff is still in the mix to start at safety. He's battling with Nate Allen for a starting job. Philadelphia also cut Kenny Phillips on Sunday, taking out another possible competitor.
• Bacarri Rambo, S, Redskins (Round 6): Rambo remains a work in progress, but he will be in Washington's secondary for Week 1, barring a late injury. The Redskins lost their other rookie safety, Phillip Thomas, to a knee injury earlier in training camp. Rambo had 16 interceptions and made more than 200 tackles during his four-year career at Georgia.
• Tommy Bohanon, FB, Jets (Round 7): The 215th pick is another player with a starting opportunity because of injury -- in his case, Lex Hilliard's broken scapula opened the door. Bohanon played 33 snaps in New York's 37-13 win over Jacksonville on Aug. 17 -- about the same number as the starting offensive line. The Jets do not figure to use their fullback that frequently once the season begins, but having a quality lead blocker certainly would help the running game.
• Paul Worrilow, LB, Falcons (UDFA): Worrilow, signed out of Delaware, burst onto the scene with a 12-tackle performance against the Bengals in a 34-10 loss on Aug. 8. He followed that showing with six more tackles in a 27-23 loss to the Ravens in Baltimore a week later. At this point, it would be tough for Atlanta to keep him off the final roster. It only adds to Worrilow's value that he can also be a menace on special teams.
• Matt Furstenberg, TE, Ravens (UDFA): While there certainly are no guarantees, Baltimore's decision to cut veteran TE Visanthe Shiancoe bodes well for Furstenberg's chances to stick. He still has Billy Bajema, Dallas Clark and Ed Dickson to deal with, but the Ravens' coaching staff has been happy with the Maryland product. Furstenberg has four catches for 54 yards this preseason.
• Jeff Tuel, QB, Bills (UDFA): Will he be Buffalo's starting quarterback in Week 1? Tuel, out of Washington State, certainly would not be the team's first choice, but with both Kevin Kolb and rookie E.J. Manuel injured, he may have to take the reins. Tuel was 10-of-17 for 63 yards in a 30-7 loss to the Redskins in Washington on Saturday, and he completed 19-of-23 passes with a pair of TD strikes in the Bills' 44-20 win over the Colts on Aug. 11.
• LaAdrian Waddle, OT, Lions (UDFA): "Frankly, it kind of bewilders me how he didn't get drafted," Detroit quarterback Matthew Staffordtold MLive.com after a 40-9 win over the Patriots last Thursday. In that game, Waddle, a talented Texas Tech prospect, split first-team reps at right tackle with Jason Fox. Waddle seems a virtual lock to claim a spot on Detroit's final 53-man roster, and he may even cement a spot in the starting lineup before Week 1.
• Kenbrell Thompkins, WR, Patriots (UDFA)/Zach Sudfeld, TE, Patriots (UDFA): A pair of finds for New England on the free-agent market. Sudfeld has pushed for playing time this preseason, with the Patriots in need of reliable tight ends. He took a step backward in the loss to the Lions, though, fumbling in the red zone -- a miscue that earned him a trip to the bench.
Thompkins, meanwhile, saw 12 targets in that game and made eight catches, burning both veteran CB Chris Houston and rookie Darius Slay. Thompkins has forced his way into the New England's starting 11, and he already seems to have a nice rapport with Tom Brady.
•Russell Shepard, WR, Eagles (UDFA): At one point during training camp, Shepard had crept onto Philadelphia's first-team offense. He's slipped into a fight just to make the roster now, but the work he did earlier may land him a job, be it with the Eagles or with somebody else.
Willie Jefferson, OLB, Texans (UDFA):