Double ditto on everything Steve said.
It's too high, but:
For most positions, players entering their 4th year are pretty much done ascending. But many OLmen keep getting better until their bodies start to fail. And as Steve said, Bahktieri is ascending.
17M guaranteed this year and 10 next; GB has some injury protections early in the contract and performance protections toward at the end of the contract.
The cap is projected to increase more than 12M per; this deal might look much better in 2 -3 years even if Bahktieri doesn't improve much.
He's making about 1.8M this year; so we're paying under $54M for 5 years. That is about right.
If we look at some of the other top 5 paid LTs: Trent Williams; Eric fisher, this looks pretty good.