First, the details.
Verlander signed a 5-year, $140 million dollar extension today. It will pay him $28 million dollars a year in 2015 through 2019. There is a 2020 option at $22 million that will vest automatically (but the terms of how that could vest are unknown at the moment). Verlander was already signed at $20 million for this year and 2014; those values do not change.
This deal is oddly similar to the Hernandez one. In Hernandez' deal, the Mariners essentially extended Hernandez for 5 years at $134.5 million dollars. Hernandez was scheduled to make $19 million in 2013 and $20.5 million in 2014. Hernandez then makes around $26.5 million a year for the same timeframe as Verlander.
I think this deal probably makes less sense for the Tigers than Hernandez' did (though Felix's deal apparently helped pace the market). They are essentially the same pitcher, with Verlander being more effective in the past few years while Hernandez was better earlier on. The problem is that Hernandez' deal goes from age-26 to age-33; two prime years and the start of the gradual tail. Verlander just added on age-32 to age-36; those are all decline years, no doubt about it. Compound the fact that Verlander already has 1553 innings on his arm (he's had 7 years in the majors and has put 9 years on his arm), and you've got a chance to look really, really foolish in 2016.
All I've got to say is that Clayton Kershaw is going to get a ridiculous, ridiculous, RIDICULOUS amount of money.