https://www.overthemonster.com/2020/12/11/22166800/boston-red-sox-offseason-preview-kirby-yates-free-agent
"After being selected off waivers by the San Diego Padres in 2017, Yates has been one of baseball’s most consistent relievers. He’s great at keeping the ball in the park, strikes out a ton of batters, and limits walks. In 2019, not only were his both ERA and FIP below 1.40, but he was among the top two in home runs allowed per 9 innings, top five in strikeouts per nine, and top 15 in walks per nine. He finished second in all of baseball in fWAR (and first in the National League) among relievers that year. On top of all that, both his ERA and walk rate have improved in each of his 3 full years with the Padres.
One of the main reasons for Yates’ production with the Padres is the development of his splitter. Not coincidentally, he introduced this splitter when that breakout first happened in 2017, and has had immense success using it. Since its introduction, opposing hitters have never recorded a batting average above .165 against the pitch."
I'd take almost any professional reliever at this point. The further away we get from the 2020 bullpen, the worse it smells.