Yeah they will, they literally do it every year with players who actually far exceed their contracts all the time.
The league rarely ever pays fair market value. The overwhelming majority of players in the league are not playing on contracts that equal in value to their production output. QB's are really the only ones getting paid in guaranteed money that is equivalent to their production.
For a DL to get paid, he has to put up Myles Garrett type of numbers over a 4+ year period. Shemar is not going to do anything close to that. So, in what scenario does Shemar get a really good guaranteed money deal on contract #2?
Like I said, unless Shemar plays like an All-Pro for the next 4 years, there's literally no circumstances where his 2nd contract is going to be anywhere close to market value.
I'm willing to guarantee right now, that he will not even be in the top 10 paid DE's 4 years from now.