The second day of on-field workouts at the NFL Combine is highly regarded as one of the most exciting days of the week. The quarterbacks, wide receivers, and tight ends hit the field on Saturday to showcase their skill sets in both traditional combine and position-specific drills.

Check out the top storylines from Day 4: 

1) Who Stood Out Among the Quarterbacks?

Depends on who you ask. According to the NFL Network's Mike Mayock, all of the top quarterback prospects brought something unique to the field on Saturday.

For USC's Sam Darnold — who chose not to participate in throwing drills — Mayock was disappointed he couldn't see the quarterback's arm. But Darnold was able to show off his legs with a 4.85 40-yard dash.

Darnold's pre-draft roommate, former Wyoming quarterback Josh Allen, put his incredible throwing arm on full display. During the quarterback position drills, Allen launched deep ball after deep ball, including this 60-yarder:

Rounding out the day's standouts are UCLA's Josh Rosen, Louisville's Lamar Jackson, and Oklahoma's Baker Mayfield.

Mayock raved over Jackson, calling him the most "spectacular athlete in this draft." Though various clubs did express desire to see him in receiving drills, Jackson has been adamant about his status as a quarterback — and was able to impress with his accuracy in position drills.

Rosen and Mayfield both put their best foot forward, positing 4.92 and 4.84 40-yard dash times and 31.0- and 29.0-inch vertical jumps, respectively. Rosen was particularly impressive in the throwing drills, connecting with Alabama wide receiver Calvin Ridley on a perfect deep ball:

**2) The Draft's Fastest Man — LSU's D.J. Chark:

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Last year's combine ushered in a new record for the 40-yard dash, set by Washington wide receiver John Ross who ran a 4.22. And while there were no records broken in the event this time around, once again the wide receivers brought the heat.

According to the NFL’s Daniel Jeremiah, LSU wide receiver D.J. Chark was in the second-round range before Saturday. But after solidifying his title as "The Draft's Fastest Man," with a 4.34 40-yard dash, Jeremiah said he would be surprised if Chark was not a top-50 pick in April.

In total, 13 wide receivers posted sub 4.50 times.

3) Griffin Continues to Defy the Odds:

When the 2018 Reese's Senior Bowl took place in January, UCF linebacker Shaquem Griffin had not yet received an invitation to the NFL Combine. Fast forward less than two months later, and here Griffin is — putting on a show at Lucas Oil Field in Indianapolis.

Griffin has been one of college football's most inspiring stories over the past two years. He lost his left hand to a birth defect at age four, but has overcome the obstacle to become one of the best linebacker prospects in this draft.

And when the linebackers' group participated in the bench press drill, Griffin put up an incredible 20 reps of 225 pounds. Notable players who did not reach 20 bench press reps at the Combine include Pro Bowl and All-Pro defensive end Calais Campbell and Super Bowl XLIX Champion Jamie Collins Sr. There were also several offensive lineman with fewer bench reps than Griffin, like Oklahoma's Orlando Brown (14).