Mixed bag for wideouts on Day 1

MOBILE, Ala. -- The first day of practice at the 2009 Under Armour Senior Bowl was notable for a few reasons, including the absence of a pair of big-name prospects.

Georgia Tech DE Michael Johnson was a late scratch, and there are mixed opinions about the reason he is not in Mobile. Some are saying he's letting a minor but lingering shoulder injury rest. Others theorize he simply isn't motivated to deal with what tends to be a mentally and physically grueling week for NFL draft prospects. Either way, Johnson's no-show is being frowned upon by NFL decision-makers. Johnson has the skills of a top-10 player, but he has frequently performed like a middle-round pick. Some have questioned his commitment to the game, so scouts should be planting red flags firmly next to his name.

Michigan State RB Javon Ringer was a late scratch as well. And while there is no official word as to why Ringer will not participate, he is missing out on an opportunity to prove himself as a receiver out of the backfield and on special teams.

North team buzz

• It's especially tough to evaluate linemen in a first-day practice in shorts and shoulder pads, but Boston College DT B.J. Raji is the clear front-runner to emerge as the top lineman from either side of the ball. Raji showed excellent lateral mobility and initial quickness during one-on-one pass rush drills today.

• California's Alex Mack and Oregon's Max Unger are Scouts Inc.'s top two center prospects and are playing next to each other this week. Mack lines up at left guard when Unger lines up under center and vice versa; both fared well at guard on Day 1. Showing that kind of versatility can only help their draft stock, but like Raji they will also give a more accurate read when they are in full pads.