How much tinkering will Musgrave have to do with the first Eagles quarterback since Tommy Thompson in 1948 and 1949 to lead the NFL in passer rating?
What has Musgrave particularly excited is Foles' progress in the pre-snap phase of offseason practices.
"We know he's a gifted athlete. He can throw the ball exactly where he wants to," Musgrave explained, per the Philadelphia Daily News. "He can add air, add touch. He can add velocity and really drive it when it's needed. But to see the way that he can visualize formations, coverages, and process what he sees has been impressive."
Game Rewind shows Foles as a smart, highly accurate quarterback. What it doesn't show is the degree to which his NFL record-breaking 27:2 touchdown-to-interception ratio is a product of Chip Kelly's innovative offense and the surrounding talent.
It's an excellent sign, though, that Musgrave already has noticed a precociousness in those pre-snap diagnoses that cagey veterans Peyton Manning, Tom Brady, Drew Brees and Philip Rivers have mastered.
That savvy should help Foles avoid a slump that often hits quarterbacks in their second year as an NFL starter.
"Windows will get tighter, defenses will try to bring stuff that'll stop you," Foles acknowledged late last month. " ... They have more on you, they know your tendencies so that's why we have to keep working."
If Foles is going to be Kelly's quarterback for the next 1,000 years, those pitfalls will have to be side-stepped.