The Green Bay Packers need more from their pass rush, so while adding a pass rushing defensive lineman should be their top priority, I wouldn't object if they opted for a pass rushing outside linebacker instead. But this doesn't appear to be the draft to find a linebacker with a first round grade.
If South Carolina's Melvin Ingram is considered a defensive lineman, then there are only three linebackers who should be taken in the first round according to CBS Sports.com: Boston College's Luke Kuechly, and Alabama's duo of Courtney Upshaw and Dont'a Hightower. Unfortunately Kuechly and Hightower are inside linebackers.
Kuechly is a tackling machine who ran a 4.5 40-yard dash with a 38-inch vertical leap. According to Roll Bama Roll, Hightower "solidified his draft stock" while Upshaw, who didn't appear to do anything to hurt his draft status, "opted not to run the 40-yard dash" while not explaining why. Upshaw in particular would be a fantastic fit with the Packers, but he's currently projected to be taken by the Bills with the No. 10 overall selection. It's unclear what role either Kuechly or Hightower could play for the Packers, assuming neither of them could start ahead of A.J. Hawk or Desmond Bishop.
West Virginia's Bruce Irwin has been getting noticed lately, and he'll get a lot more attention after running a "mind-blowing" 40-yard dash time of 4.43. However, he'll still have to answer questions as to why he was benched during his senior season. North Carolina's Zach Brown is incredibly fast and a track star, but he might be undersized (236 lbs.) for the Packers 3-4 scheme. California's Mychal Kendricks "dominated Monday's workouts" by finishing first in the broad jump, vertical jump, and 40-yard dash among linebackers. But he came to the combine with a fourth or fifth round draft grade. His low draft grade isn't because he was unimpressive in college, he was Pac-12 Defensive Player of the Year, but at 5-11, he has less than ideal height. There's some potential among these players, though none of them should be taken in the first round.