Darnold furthered his case, throwing passes in front of scouts on a rainy Pro Day in Los Angeles.
"Quarterback pro days are heavily rehearsed, following a custom script, and Darnold's pro day wasn't any different in that regard," said NFLDraftScout.com senior analyst Dane Brugler.
"However, the heavy rains were unscripted and could have been a disaster for Darnold, who opted not to throw at the Combine, putting all his chips in the middle for this workout. I though he passed with flying colors, delivering accurate balls that cut through the wind and rain.
"Some of the heavy balls wobbled and there were double-digit drops by receivers, but it was an impressive showing. He made numerous difficult throws. He only helped himself."
NFLDraftScout.com rates Darnold as the No. 2 prospect in the draft, behind Penn State running back Saquon Barkley, although the Browns, assuming they keep the pick, are expected to select a quarterback.
Darnold said he had dinner and meetings with the Browns' top brass on Tuesday, one night after doing the same with the New York Giants, who hold the No. 2 pick.
"It would be awesome to go to No. 1, just because I think what the Browns are doing is really good right now," Darnold said in an ESPN interview. "I think they have potential to be a really good team in the future. Just based on that, yeah, a part of me really wants to go No. 1."
Darnold, the only top quarterback prospect who did not throw at the NFL Scouting Combine last month, said he was pleased with his effort on Pro Day, when he took his snaps from under center to show off the footwork and drops needed at the NFL level after working from the shotgun in college.
"Just kind of proving exactly what I proved on tape -- that I can throw on the run, throw with accuracy," Darnold said on the NFL Network. "I think I did a really good job of being aware of keeping two hands on the ball, too, when I was in the pocket. I know some guys were looking at that.
"Just being aware of all those little things and then coming out here and ripping it. I thought I did a pretty good job."
Ball security has been a nagging concern after Darnold lost nine fumbles last season as a redshirt sophomore. That Darnold mostly threw in the rain Wednesday was a bonus, as the quarterback-needy teams near the top of the draft -- Cleveland, the New York Giants, New York Jets, Buffalo and Denver -- all play outdoors in cold-weather environments.
"I knew I wasn't going to have a problem with it; I thought I made the most of it," Darnold said of the rain. "I have been training really hard for this day."
Some teams near the top of the draft might prefer the throwing mechanics of UCLA's Josh Rosen, or the stature and best-in-class arm strength of Wyoming's Josh Allen, or the moxie and accuracy of Oklahoma's Baker Mayfield.
The elite athleticism of Louisville's Lamar Jackson also puts him in the discussion for the top half of the first round.
Darnold might have the best blend of all those skills, with above-average arm strength and accuracy on the move, as well as plenty of intangibles.
USC coach Clay Helton told the NFL Network that Darnold was "the best one-on-one leader I've ever seen."
Darnold completed 303 of 480 passes for 4,143 yards, with 26 touchdowns and 13 interceptions, last season. He threw 31 touchdown passes a redshirt freshman.
"He has put in all the work he needs to on tape," Helton said Wednesday before Darnold's workout. "This is icing on the cake."