"Garbage" MLB starters put up the following batted ball stats?
BABIP: .260 (T 16th among MLB starters)
GB/FB: 2.56 (T 7th among MLB starters)
GB%: 58.1% (4th among MLB starters)
LD%: 19.2% (26th among MLB starters)
Hard Contact%: 24.1% (T 15th among MLB starters)
LOB%: 80.4% (10th among MLB starters)
You can't simply look at K, BB, and Swinging Strike rates and form some sort of all-conclusive judgement. Nobody on here is arguing that Sanchez is pitching at an elite level, but to go out and make statements such as "he's the worst starter in the league" is an absolute joke. If you're going to act like some sort of Bill James wannabe, you can at least go into ALL of his advanced stats and try and decipher why "the worst starter in MLB" is currently fielding a 3.55 ERA despite battling atrocious K/BB rates for the majority of the season.
Let me guess, its all "luck"? Potentially....or he is simply incredibly hard to hit, as evidenced by his well above-average batted ball profiles. What do we know about balls hit in play? Line drives are bad (Sanchez is above-average in this regard), ground balls are good (Sanchez is elite in this regard), and his elite hard-contact percentage means that all of those ground balls he induces are easily fieldable by the infielders behind him, because ultimately it is going to be the hard hit groundballs that will make it past defenders.
Pitchers who are hard to hit DO exist. These guys CAN get away with putting balls in play, because they typically induce contact that is easy to field. FIP and xFIP has no answer for these pitchers.