No, he had WAR numbers of 0.5 and -0.2 in 2015 and 2017 (see what I did there), which is closer to terrible than ok (I don't want to turn this into another 'WAR is worthless' argument, but yeah.., just please everybody at least put a prefix letter in front)
In 2017 his ERA+ was somehow average, which seems ok, so I thought that's what you were referring to, but his peripherals were mostly worse, his FIP was a good bit worse, because he led the league in HR allowed, and his WHIP was worse (almost 1.4) and his bWAR was worse (negative even), so maybe 2015 then, but his fWAR was better in 2017, so maybe 2017, but if you prefer fWAR then you should prefer FIP, so maybe 2015, so yeah I had no idea which one was ok. I'll upgrade his two 'terrible' seasons to 'pretty bad'. Terrible was too harsh, he could've definitely been worse.
I thought the extension was a bad move at the time and I still think it was a bad move (if he was allowed to become a FA, what would he have got on the open market). Although I think it's worked out just fine so far.