Sounds like the main issue is that the position group is "LB". And part of that position group is OLB in the 3-4 defense, which we know are your edge rushers, which is a totally different position (and far more highly paid) than what Quay Walker plays. Which means, the top 10 salaries for Walker's position are artificially inflated, and so the 5th year option for a player playing Walker's position is simply out of range.

Actually makes sense... I hope Walker (and his agent) also see it that way.