https://blogs.fangraphs.com/red-sox-extend-one-of-this-seasons-best-relievers/
Fangraphs write up. Didn't know Barnes will wind up with 3rd most appearances for a Sox pitcher sometime next season.
To get to this level of dominance, Barnes made an important count-based change. Ben Clemens wrote about Barnes’ “one simple trick” for success back in May, noting that Barnes’ absurdly-high 0-0 count zone rate helped yield more success on his curveball, which he has relied on more when ahead in the count than in years past. It’s seemingly simple, then: If Barnes can get ahead in the count more often, he can thus throw his curveball more often and ultimately get more hitters to whiff. That was Ben’s conclusion in a nutshell, but the more granular breakdown is an enjoyable read. Barnes has a near-70% first strike percentage this season, which is the sixth-highest rate among pitchers with 30 innings; his year-over-year increase of 9.1 percentage points is also the 18th-largest increase in baseball, minimum 20 innings pitched in 2020 and 30 in ’21. Overall, Barnes has thrown 35% of his pitches this season while ahead in the count, ranking as the 12th-highest mark among the 329 pitchers who have thrown at least 500 pitches.