INDIANAPOLIS -- The offensive linemen and tight ends took to the field at Lucas Oil Stadium as the workouts for the 2013 NFL Scouting Combine kicked off in earnest. There were plenty of athletic prospects at both positions and players who really improved their draft stock. Here are the 10 most impressive workouts from day one.
Jonathan Cooper, North Carolina: Cooper impressed scouts the minute he arrived in Indianapolis tipping the scale at 313 pounds and completing 35 repetitions of 225-pounds on the bench press. Both marks pleasantly surprised NFL scouts. He clocked 5.11-seconds in the 40 then effortlessly moved his large frame around the field. Cooper entered the Combine as a mid-first round choice, but will now receive consideration as a top 10 pick.
Terron Armstead, Arkansas Pine-Bluff: The small-school prospect turned in an eye-popping workout. Armstead's 40-time clocked in at 4.72 seconds while his other marks included 31 reps on the bench press, a vertical jump of 34.5 inches and a broad jump that measured 9-4. Armstead is now being talked about as a potential second-round choice.
Eric Fisher, Central Michigan: Fisher impressed during the testing and drills portion of the Combine. His marks included a 40 time of 5.03 seconds and 4.41 seconds in the 20-yard shuttle. Fisher showed the uncanny ability to keep his long frame low to the ground and continues to prove he's the complete package.
Lane Johnson, Oklahoma: The former tight end displayed his natural athleticism, timing the 40 in 4.75 seconds and posting a vertical jump which measured 34 inches. He translated his athleticism onto the field during drills and Johnson's Combine performance should push Johnson into the middle portion of round one.
Tyler Eifert, Notre Dame: Eifert staked his claim to being the first tight end selected in April's draft timing 4.65 seconds in the 40, touching 35.5 inches in the vertical jump as well as posting a broad jump of 9-11. He kept the momentum going during position drills displaying next-level receiving skills and may break into the top 20 picks based on his results.
Zach Ertz, Stanford: Ertz was middle of the pack during the testing portion of the workout, but his pass catching performance was another story. Ertz ran sharp, crisp routes and looked like a receiver in a tight end's body.
Chris Gragg, Arkansas: Gragg opened the day by running the 40 in 4.49 seconds, the fastest of any tight end in attendance. His other results included a vertical jump of 37.5 inches and broad jump of 10-5. Gragg looked athletic during position drills, rarely dropping a pass and displaying an undeniable downfield burst to the long ball.
Vance McDonald, Rice: McDonald has been steadily rising up draft boards and once again impressed scouts. He looked athletic during position drills and showed the ability to effortlessly make the deep reception in stride. McDonald's Combine workout will move him into the draft's initial 45 selections.
Brian Schwenke, California: Schwenke was the most athletic center on the field Saturday and stood out during position drills. He showed tremendous quickness, movement skills and has moved into the top 90 picks of the draft.
Dion Sims, Michigan State: Sims looked impressive on the scale and during the workout. He measured 6-5 and 262 pounds then timed 4.72 seconds in the 40. He looked fast in practice and ran better than expected routes.
Tony Pauline is the editor of DraftInsider.net and is also a contributor for USA Today. For the latest buzz surrounding the NFL Draft follow him on Twitter @TonyPauline*