IN THE spring a young man's fancy lightly turns to thoughts of ... blitz pickups? � Around the blessed time that sun dresses start to appear on campus, football players begin buckling their chin straps for the less cheery rite of spring practice. The football field in March and April becomes a laboratory and proving ground. � Little known fact: NFL teams with a new head coach are awarded an extra minicamp, giving players time to digest strange schemes and terminology. Not so at the (ahem) amateur level. The NCAA allows each Division I-A team—new coach or not—15 spring workouts over a 29-day period. � Offensive packages are installed; underclassmen, especially freshmen who red-shirted the previous fall, are given long and searching looks; and depth charts come into sharper focus. SI checked in on four programs where the urgency was especially intense.