Harrell passed for more than 15,000 yards during his three years as a starter for Leach at Texas Tech, and finished his career with more completions and passing TDs than anyone in NCAA history. He now plays for the Green Bay Packers.
Mastrole said he considers Bender one of his "Super Select" prospects. He said the Fort Lauderdale/Cardinal Gibbons High product has one of the quickest releases in the entire country, and an arm that gives him the ability to "whip it 20-30 miles-per-hour in any conditions."
"The kid is pretty polished," Mastrole added. "I think he has the real ability to be a three-year starter at Washington State after taking in the program for a year or two."
Bender isn't just receiving props from Mastrole these days. Elite 11 guru and former NFL quarterback Trent Dilfer recently praised Bender for his play at the Elite 11 event in Columbus, Ohio.
"Kid is going to throw for a billion yards at WSU," Dilfer tweeted. "Gave him some tools to be more consistent."
One of those tools is footwork.
"We're going to get back at it in a few weeks here," Mastrole said of his work with Bender. "He's still learning where to slide around in the pocket to find all of his reads, as well as getting his footwork on point."
Having taught the likes of Manual, a first-round pick in April's NFL draft, plus nine current Division I quarterbacks, Mastrole knows what it takes for a quarterback to make the transition from one level to the next.
He said he believes the transition to college for Bender should be fairly easy.
"Bender's high school runs virtually the exact same offense they run at Washington State," Mastrole said. "He should be able to pick up the playbook almost immediately and fit in quickly.
"Peyton will definitely come in and fight for time, but it will be thanks to his work on the field," Mastrole said. "He'll be all business when he gets there."
Mastrole calls Bender "a great kid coming from a great family," and notes that he's a "smart kid who works hard and gets good grades."
The admiration is mutual.
"Coach Mastrole is a great guy to work with," says Bender. "He really focuses on trying to work with your mechanics rather than try to completely change them like many other QB coaches do."