https://www.youtube.com/watch?v=gBWXCSU4nHQ
I am usually not one to make bold claims, but Kimbrel had a spectacular September. He may have only pitched 7.1 scoreless innings, but it was how he pitched those innings that gives them significance. He dominated striking out 13 batters and walking none.
You can fake a good ERA for 7.1 innings far easier than you can fake those kind of walks and strikeouts. In 2020, there were 48 outings where the starting pitcher lasted 7.1 innings or more. 21 of these 48 outings were scoreless - inflated due to survival bias but hear me out. These 21 outings featured esteemed names like Jacob deGrom, Trevor Bauer, and Aaron Nola. However, it also features some players who may have lucked into the great outing such as Brad Keller (9 IP, 1 BB, 2K), Tyler Anderson (9 IP, 0 BB, 4 K), and Alec Mills (9 IP, 3 BB, 5 K).
These were still skillful outings, but the lack of strikeouts means they were up to the luck of balls put in play; inducing soft contact is more variable than punching out waves of hitters. Looking at all outings this year, only one player managed to strikeout 13 batters in a game while walking none: soon-to-be unanimous AL Cy Young winner, Shane Bieber.
Obviously there is a difference between doing it in one start (like Bieber) as opposed to eight relief appearances (like Kimbrel), but it proves a point: Kimbrel's September indicates a change not because it was scoreless, but because it was scoreless in such a dominant fashion.
Craig Kimbrel may not be fully rehabilitated - his Release Point Variability was up a little in his 9/26 outing - but he has clearly taken some steps in the right direction in 2020.