During the first few minutes of the Eagles' rookie minicamp practice last Friday, Doug Pederson did what everyone expected him to do. No, he did not rock to the gentle groove of the Ghost Town DJs' "My Boo," the first song to play at Pederson's first practice as the Eagles' head coach. Instead, he focused his attention entirely on quarterbacks Carson Wentz and Everett Golson, crossing his arms and eyeballing them as they went through a series of elementary drills: dropping back, pantomiming handoffs and play-action passes, tossing the football to a nearby member of the coaching staff.

Ever since hiring Pederson in January, the Eagles have offered his experience working with and coaching quarterbacks as the predicate for choosing him as their head coach. "Terrific, just terrific," owner Jeffrey Lurie said, referring to 2011 and 2012, Pederson's two seasons as the Eagles' quarterbacks coach. Then Pederson was Andy Reid's offensive coordinator for three years with the Kansas City Chiefs, and Alex Smith was quite effective there. So that section of Pederson's resume was in bold type for Lurie, too.

Pederson himself considers his extensive familiarity with good quarterback play to be his greatest qualification. Asked earlier this week why he was the right coach to develop Wentz, the Eagles' presumptive franchise quarterback, Pederson cited his time as a teammate of Dan Marino, Brett Favre, and Jim McMahon - his chance to see what those accomplished quarterbacks did and how they did it - as essential to his expertise.

"That's first and foremost," he said. "Having 17 games to actually start in this league, to understand what it means to stand in front of the media, to stand in front of your teammates, to lead your teammates as a player, I think those are important. Those are things you can build with a young quarterback. On top of that, just my experiences as a coach, being able to study tape and study the offenses and study technique and understand where to put my eyes, how to drop. . . . Those are things you learn to appreciate, and then you can pour it into a young quarterback."

It all sounds wonderful, and it may very well turn out to be, for Wentz and the Eagles. Maybe Pederson will come to be known as a quarterback guru, the perfect coach both to extract excellence from Sam Bradford and, over a longer period of time, to coax greatness from Wentz. But just because the Eagles insist Pederson will be that coach, and just because Pederson believes he is that coach, doesn't mean he is. If he were, it might be apparent from his experience. It's not.

When the Eagles made Pederson their quarterbacks coach, it was his first significant job as an NFL assistant. Those were tumultuous seasons for the franchise: the Eagles' 12-20 record; the buildup, the crashing, and the burning of the "Dream Team;" the end of Reid's 14-year tenure as head coach. To say that there were mitigating factors then, that any evaluation of the Eagles' quarterbacks over those two years will be inherently incomplete, is undeniable.

Nevertheless, the numbers are what they are. In 2011, Michael Vick, Vince Young, and Mike Kafka combined for a mediocre 59.8 completion percentage and an interception percentage (4.5) that was higher than their touchdown percentage (4.0). Vick had been an MVP candidate in 2010, yet Pederson did little or nothing to prevent a regression in Vick's play. Completion percentage, yards per attempt, touchdown percentage: For Vick, each of those figures fell from 2010 to 2011, then fell again from 2011 to 2012. And remember: the talent that had made Young the No. 3 overall pick in the 2006 draft, by the Tennessee Titans, remained untapped with Pederson: In six games, Young completed fewer than 58 percent of his passes, threw four touchdowns and nine interceptions, and posted an awful 60.8 quarterback rating. (Contrast those performances with the statistical improvements that Nick Foles, Mark Sanchez, and Bradford made under The Coach Who Shall Not Be Named And Who Would Not Open His Heart.)

OK, but Smith's first three seasons in Kansas City represent a feather in Pederson's helmet, no? The Chiefs' record with Smith was 30-16, and his stats are more than respectable: a 63.7 completion percentage, a 4.2 touchdown percentage, an average of 7.0 yards per attempt, a 92.5 quarterback rating. That's good stuff, and Pederson can take some credit for it.

What Pederson can't take credit for, though, is transforming Smith from a potential bust, as the No. 1 overall pick in the '05 draft, to a reliable NFL starter. Smith already had undergone that metamorphosis with the San Francisco 49ers. Over his 25 games under head coach Jim Harbaugh and offensive coordinator Greg Roman, Smith's completion percentage (64.3), touchdown percentage (4.5), yards per attempt (7.4), and quarterback rating (95.1) were higher than they were under Reid and Pederson.

Again, this history doesn't mean Pederson will be a failure or Wentz is doomed to become the 21st century's answer to Ryan Leaf. It means Pederson's presumptive strength as a head coach remains, for the moment, an open question. The Eagles say he's terrific with quarterbacks. He says it, too. It's what they and everyone else expect from him. But saying it doesn't make it so.

msielski@phillynews.com

@MikeSielski