Inside the draft room at Lambeau Field, the Packers have two walls literally covered with names of college football players.   One board ranks the players vertically, the top NFL prospect in their minds, followed by the second best player and so on.  There's another, horizontal board that grades players across based on the position they play.  Once the Indianapolis Colts take Andrew Luck's name off the board to open the 76th draft tonight, the fun begins.   General Manager Ted Thompson removes Luck's name on both boards and as the process continues, he can, at a glance, see which player is highest rated when number 28 comes around, based on overall ability, and compared to similarly ranked players at other positions.   So when the Packers pick, they'll have to decide if, hypothetically, Guard David DeCastro of Stanford is still out there, and he's highest rated on the vertical board, versus Nick Perry, the USC Defensive End or Shea McLellin of Boise State, the top linebacker on the horizontal comparison, it's time to decide on value versus need.   Not an easy proposition and it actually gets easier the deeper the draft goes.  That's because no two teams have players ranked equally when you're talking the 120th or 200th ranked player.   Names get plucked in short order unless deals are made to go up and grab the player you have ranked highly, or trade down in the hopes that a player you've ranked high is falling and likely to be around when your turn comes up again in the next round.   Where teams hurt themselves in this process, is to reach for a player who is well below your list of the top athletes remaining, just to cover a need.   If that pick doesn't pan out, it's double trouble, the hole still remains on the roster and you've missed out on a good football player you didn't need at the time, but certainly could use a year or two down the road.  Thompson will stay true to his boards.   There will be a handful of defensive players on those boards when pick 28 arrives tonight, will it be McLellin? Perry? Perhaps Jerel Worthy, the big Michigan State defensive lineman, or Devon Still of Penn State.  Safety Harrison Smith of Notre Dame is a player I like a lot, but maybe not at 28.  Which such a glaring hole at safety, Thompson might consider trading out of round 1, picking up a couple more choices and grabbing Smith at say, number 35 overall.  He's done this before, with Jordy Nelson in 2008.  He went from 30 to 36 with the Jets to pick a player at a position that already had Donald Driver, Greg Jennings and James Jones.  Keep in mind, tonight is the splash, the meat follows with rounds 2 and 3 Friday night and the final four rounds Saturday.    On the link below, comments of Thompson on the final installment of our draft preview series which has been sponsored by Nicolet Bank.