No doubt the plan to move on without their top receiver a year after setting franchise records for yardage and points was carefully constructed by Philadelphia Eagles coach Chip Kelly. No doubt it also could blow up in his face if Jeremy Maclin cannot deliver this season. For 20 seconds or so following what turned out to be the final play of practice at their organized team activities last Monday, that was something everybody began to ponder silently. Maclin, coming off reconstructive ACL surgery less than a year earlier, was on the ground, clutching his left knee, not getting up. Not until he was able to rise and walk without assistance back to the practice-ending huddle was everyone able to breathe again. Before that, it was as if all of the oxygen had been sucked out of the NovaCare Complex by a giant, invisible vacuum.