For our defense, all things being equal, I'd rather have Kruger than Spencer. Nothing wrong with Spencer, but he's older, has injury history, and isn't as good in coverage. I'd rather give Kruger the $8m/year than Spencer at this point.
As for the contract, let's look at some details of a potential five years, $40m agreement. Let's say it includes $10m in upfront bonuses ($4m signing bonus, $6m roster bonus in 2013), and a fully guaranteed first year salary of $2.5m. That's $12.5m in cash in Year 1. Let's also say the second year salary is $7.5m, and $5m of that becomes fully guaranteed as of February 10, 2014. That's $17.5m in essential guarantees. Here's what it looks like on a year-by-year basis:
Year 1: $1m signing bonus + $6m roster bonus + $2.5m base salary = cap hit $9.5m in 2013
Year 2: $1m signing bonus + $7.5m base salary = cap hit $8.5m in 2014
Year 3: $1m signing bonus + $6.5m base salary = cap hit $7.5m in 2015
Year 4: $1m signing bonus + $7m base salary = cap hit $8m in 2016
Year 5: $1m signing bonus + $5.5m base salary = cap hit $6.5m in 2017
If we wanted to release him after Year 1 before his $5m guarantee kicks in, we would wind up with a dead cap hit of $4m in 2014. If we wanted to release him after Year 2, we'd wind up with a dead cap hit of $3m in 2015. Team friendly contract, front loaded with cash and guarantees. If it doesn't work out after two years, we would have paid him $18m. Not favorable, but it's not the kind of contract that you can't work into your cap or sustain an early termination.
Maybe that's still too much for a player with his resume. But it won't kill us.
Knock out deal for the Colts if his agent would go for something like that. They normally look for something with more "commitment" going forward than a team going on the hook for what is basically a 4 million $ signing bonus. Let's just suppose that this contract was offered to a player that had a possibility of being franchised. Why in the world would he just not take the franchise tag for say 9 million and move on the following year ? Not to say that giving a player a 50 Mill contract with a 5 million $ signing bonus is impossible ... I've just never seen one.