Pivetta is a really interesting case in that he has consistently drastically underperformed his peripherals. The strikeouts have been there, the walks a tad high but manageable, but he just gets f***ing shelled. It's insane that a guy with a career 3.99 xFIP and a 4.56 FIP has an ERA of 5.34, there's only so much you can blame on bad defense, as it's not like a .324 BABIP is exceptionally high. Is it sequencing, lack of a solid primary or tertiary pitch - as you mention, his changeup is terrible but his fastball has also been horrendous by pitch value so maybe he just can't locate it well at all? He would be a decent project to take on, will still only be 27 by season's start, maybe change his grip on some of his pitches, try attacking hitters differently, build him up as strictly a bullpen piece where his velocity will trend up, etc.