HockeyProspect have his skating rated as 5 on a 3-9 scale where 3 is "poor", 4 is "below average" and 5 is "average".
This quote also labels him as an average skater:
"To me he’s a great junior player. I know everyone loves him but he’ll need to be a winger in the NHL and I agree that he’s smart but he’s not very dynamic. He’s only 5’8” and is an average skater. Put him on North Bay and he’d be a 2nd round pick. He’s way down my list. He abused Kingston and North Bay but was very ordinary against the good teams in the West" - NHL Scout, May 2020
Regarding that scout's quote, can you link to it?
I've been searching that scouting quote and I'm unable to find a source other than it being passed around other message boards and reddit in very much the same way. And honestly, anyone saying that Rossi would be a second rounder is kind of suspect to me.
I'd agree that Rossi's speed is average to slightly above average. His agility and east-west movement is what stands out as excellent to me. When averaging between the two I'd list him as an above average skater. He won't blow your doors off but he'll get the puck into the offensive zone, draw defenders to the half wall, evade them and dish a pass to the open man without making it look super flashy. I really like his puck distribution. It's very Zetterberg-esque.
When comparing Perfetti, he's got good edges but not great. He (Perfetti) relies more on stickwork to evade opponents than Rossi and it looks really impressive in the highlight reels. Both are very adept at getting through the defense using their toolsets. I think both will find a way to make this work for them at the next level with those toolsets.
Also, here's a few reports on Rossi discussing his skating with links.
Marco Rossi Scouting Report: 2020 NHL Draft #6 - Last Word on Hockey
"Rossi is an excellent skater, with very good speed and acceleration. He combines that with outstanding agility and edgework. He can take defenders wide and then cut to the net. His ability to make quick cuts also makes him extremely dangerous in one-on-one situations."
2020 Draft Profile: C Marco Rossi - The Draft Analyst
"Rossi is a consistent breakaway threat, but he also contributes in other areas thanks to a high-end motor, strong balance on the puck and an acute grasp of how plays will unfold before him."
https://thehockeywriters.com/marco-rossi-2020-nhl-draft-prospect-profile/
"His awareness and vision are off the charts. But then in a flash, he’s gone because his skating is very much above average in both acceleration and straight-line speed. He can beat opponents on the rush and can also track you down from behind if necessary."
2020 NHL Draft Profile: Marco Rossi
"This strength translates to a powerful skating stride, which Rossi can use to generate some separation at the OHL level. While he doesn’t have the same top gear as Quinton Byfield, Rossi’s made strides with his acceleration. I’ve seen reports call him a “four-directional skater” "
2020 NHL Draft prospect profile: Marco Rossi scouting report
"Rossi is a very fast skater, however, he isn’t perfect. He needs to work on his first-step and acceleration, as he somewhat lacks in those areas. You can tell it takes him a few strides before he hits his full-speed, and with the ever-evolving speed in the NHL, it makes what seems like a small set-back a major one."
Marco Rossi - NHL - DraftSite.com
"More shifty than explosive but moves so well East-West,"
and
"A smart playmaker with excellent East-West lateral movement."
Marco Rossi - NHL Prospect Scouting Reports - Rubyiss
"Marco Rossi is a very good skater but needs to develop more top end speed. Marco uses and has excellent edgework and balance. Often beats defenders on on one with his excellent puck handling abilities. Marco is very athletic on his skates and possesses excellent creativity. Plays a high pace game which is very suited for today’s game."
...I could go on but I've slacked off at work enough for now. My point is this: you'll find a lot more reports that Rossi is a good skater than you will reports that he's average or bad. Of the 20 or so I just flipped through I didn't see anything that said his skating was bad, or anything to corroborate that anonymous NHL scout's quote.
EDIT: Conspiracy theory here, but what if that quote was from Kris Draper who is secretly pushing Yzerman to pick Perfetti? Dun dun dunnnnnnnn