Quarterback prospect Josh Rosen participated at UCLA's pro day Thursday evening, showing off the impressive arm and throwing motion that has him in the running to be the top overall pick in this year's NFL draft. 

Sportscaster Bryan Fenley shared Rosen making a throw over the middle:

Bruin Report Online capture footage of Rosen hitting his receivers on a go route and deep post:

Alden Gonzalez of ESPN added more video of Rosen throwing a variety of routes:

"Rosen threw it well today, by all accounts," Mike Garafolo of NFL.com noted.

That shouldn't come as much of a surprise.

"I think [Rosen's] the most natural thrower of the football (among this draft class)," NFL Network draft analyst Mike Mayock told Fenley on Thursday. "He throws a beautiful ball. When he has clean feet and clear vision, I think he's the best thrower in the draft."

A number of NFL coaches and decision-makers were in attendance for the session. Per Gonzalez, the head coaches he saw included Marvin Lewis of the Cincinnati Bengals, Vance Joseph of the Denver Broncos and Anthony Lynn of the Los Angeles Chargers, while the general managers he observed included John Elway (Broncos), Mike Maccagnan (New York Jets) and Thomas Dimitroff (Atlanta Falcons).

More likely would have been in attendance had his Pro Day come on a different date:

While Rosen wasn't expected to do any of the various athletic tests Thursday, according to Gonzalez, the folks in attendance were there primarily to see him throw in the first place. Getting him into meeting rooms and picking his brain will be a big part of Rosen's evaluation as well.

At the moment, he remains a contender to be the top overall pick in this year's draft and is arguably the top quarterback in a deep and interesting class that also includes players like Sam Darnold, Baker Mayfield, Josh Allen, Mason Rudolph and Lamar Jackson, among others.

Rosen's scouting report has always taken on a consistent theme. He's the most polished thrower in this class, hands down, but there are question marks about his leadership and personality. 

"He's as talented as they come. He can make every throw that you want to see and it's easy for him," an NFC scout told Bucky Brooks of NFL.com. "I know the personality will turn some people off, but the kid can play."

"He wasn't the guy everyone rallied around in college and you don't have to dig around for too long to find people who said he was hard to coach," an NFL executive added. "He's definitely talented. Nobody questions that. But he's going to have to get grown men to buy into him as their leader. That is not a given."  

On Thursday, at least, his elite throwing mechanics and arm were on full display.