Whenever a veteran quarterback has to change play callers or offensive systems, we won’t know how harmonious the combination will be until the season begins. The quarterback and play caller will say all the right things and sing each other’s praises all offseason, but their relationship is delicate and not easily replicated.We’ll see a significant number of quarterbacks with new play callers this season. Let’s look at each situation and whether there appears to be a seamless fit or adjustments will be needed.Jalen HurtsNew Eagles offensive coordinator Sean Mannion should give the unit the biggest makeover Hurts has experienced under coach Nick Sirianni. If that wasn’t already obvious when Mannion was hired, Jeff Stoutland’s departure cements the fact that there will be wholesale changes. Stoutland was the run game coordinator and had a unique protection system that will be overhauled.Hurts is still an effective scrambler, but his ability as a designed runner has regressed in recent seasons. Without a consistent option game, an already simple Eagles system lost one of its main aspects.Mannion comes from the Packers, who were one of the best gun-run teams in the league without involving Jordan Love as a runner. They did so with motion, creative backfield actions and varying mesh points on run concepts. A lot of the backfield actions looked inspired by the wing-T offense. The Packers ranked fourth in explosive rush rate from shotgun in the last two seasons.