The immediate impact the NFL scouting combine makes on a prospect's stock can be difficult to discern, but there were plenty of eye-opening performances this year in Indianapolis.

While highly touted USC quarterback Sam Darnold opted not to throw, several other prospects in the running for the No. 1 overall selection built a strong case for themselves. However other notable names had a rough go during the drills, which could hurt them come April.

Winners

Saquon Barkley, RB, Penn State: Already the clear-cut No. 1 at his position and an almost surefire top-five pick, Barkley delivered a singular performance, further bolstering his case to be the first overall selection in the draft. His numbers were staggering: At 6-0 and 233 pounds, he ran a 4.40-second 40-yard dash, posted a 41-inch vertical leap and recorded 29 bench press reps. Even if he doesn't become the first running back since fellow Nittany Lion Ki-Jana Carter in 1995 to hear his name called first on draft night, Barkley now looks to be the pre-eminent overall prospect in this class.

Shaquem Griffin, LB, Central Florida: Barkley made the biggest initial buzz, but Griffin won the weekend. While using a prosthetic in place of the left hand he had amputated as a child, Griffin posted 20 reps of 225 pounds on the bench press. Even more astonishing was his 4.38-second 40-yard dash, the best mark for any linebacker at the combine since 2003. Griffin is a unique evaluation, but he is proving his athleticism and skill set compare favorably to past early-round linebackers.

Josh Allen, QB, Wyoming: This was the showcase onlookers were waiting for. Competing alongside the likes of Josh Rosen, Baker Mayfield and Lamar Jackson, Allen displayed the easy arm strength and impressive build (6-5, 237 pounds) and physical tools that help scouts look past a history of erratic accuracy in college. Whichever team drafts him must be comfortable that Allen's 56.2% completion rate won't follow him into the NFL. But he provided a sound response to those concerns in this setting.

D.J. Moore, WR, Maryland: Measuring in bigger than expected at 6-0 and 210 pounds, he continued to ascend with a 4.42-second 40-yard dash that ranked fifth among all receivers. A dynamic threat after the catch, Moore is drawing comparisons to former Maryland standout Stefon Diggs, now a star for the Vikings. Moore's stock is on a big upswing in a wide receiver class lacking star power.

D.J. Chark, WR, LSU: His 4.34-second 40-yard dash and 40-inch vertical were tops among receivers and ranked among the best marks for any player at the event. At 6-3 and 199 pounds, he has rare tools for a deep threat. Chark is a project because of his unpolished route running but showed why he should have no shortage of suitors.

Mike Gesicki, TE, Penn State: He made a solid case to be the top option at his position. His 41½-inch vertical (first), 4.54-second 40-yard dash (tied for first) and 22 bench press reps (second) were all among the best marks among a pedestrian tight end class. Already a dynamic receiving threat, Gesicki should draw second-day interest from a team willing to bring him along as a blocker.

Derrius Guice, RB, LSU: After an injury-riddled 2017, he reminded scouts why he engendered so much hype as Leonard Fournette's successor. The hard-nosed Guice ripped off a 4.49-second 40-yard dash and looked smooth, fueling comparisons to a young Marshawn Lynch. Guice helped solidify his case to be the second or third back taken in a group that's deep behind Barkley.

Leighton Vander Esch, LB, Boise State: With Virginia Tech's Tremaine Edmunds sitting out much of the athletic testing, Vander Esch was perhaps the standard setter among linebackers. At 6-4 and 256 pounds, he had one of the best all-around performances: a 4.66-second 40-yard dash, 39½-inch vertical leap and a 6.88-second three-cone drill. He should now be squarely in the first-round conversation.

Kolton Miller, T, UCLA: Measuring in at a monstrous 6-9 and 309 pounds, he set a record for offensive linemen at the combine with a 10-1 broad jump. More importantly for his stock, he moved well and answered some questions about his fluidity.

Jaire Alexander, CB, Louisville: Somewhat overlooked after knee and hand injuries sidelined him for much of 2017, he re-established himself despite some formidable competition. Alexander's quick feet and easy handle of the position were evident in his on-field workouts, and a 4.38 40-yard dash ranked sixth among corners. His 5-10, 196-pound build isn't prototypical for some teams, but — at minimum — Alexander can probably be universally employed in the slot.

Losers

Orlando Brown, T, Oklahoma: Seldom a showcase for offensive linemen, the combine proved to be a series of stumbling blocks for Brown. His 5.85-second 40-yard dash was the fifth-slowest at the combine since 2003, and the four players behind him went undrafted. He also notched just 14 bench press reps and repeatedly struggled in drills. For an All-American accustomed to overpowering opponents, this was quite the wake-up call.

Tarvarus McFadden, CB, Florida State: A 4.67-second 40-yard dash could prove to be an anchor on McFadden's stock, as it was the second-slowest mark of any cornerback and reinforced concerns about his long speed. Even at 6-2 and 204 pounds with a physical style of play and impressive ball skills, he could now struggle to find a spot in the first two rounds, especially given the overall depth of the position.

Luke Falk, QB, Washington State: Looking to close the gap on the top tier of passers, he instead showed how far behind he still is. He was one of the most erratic passers in drills and struggled with his ball placement. Falk's workout might not override his robust college workload, but questions still linger about how he will transition from the "Air Raid" offense.

Maurice Hurst, DT, Michigan: His combine was cut short after it was revealed he had been diagnosed with a heart condition, the severity of which is still unclear. The concern could be temporary, as former Utah defensive tackle Star Lotulelei had a similar experience in 2013 before being cleared at medical re-checks and being selected by the Panthers in the first round. Hurst will have to undergo the same evaluations, however, and he missed out on an opportunity to highlight his athleticism.

Mark Walton, RB, Miami (Fla.): As the rest of the backs wowed in drills and workouts, he seemed to fade into the background. His 4.60-second 40-yard dash was subpar, especially for a ball carrier of his build (5-10, 204 pounds). As he continues to work his way back from ankle surgery, Walton needs a strong pro day performance to prevent his stock from tumbling.

Ronald Jones, RB, USC: He joined his ex-teammate Darnold by sitting out position drills after tweaking an ailing hamstring during his 40-yard dash. The hiccup shouldn't prove too detrimental to Jones' standing, but it was nevertheless a disappointment.

Follow Michael Middlehurst-Schwartz on Twitter @MikeMSchwartz