Kimbrel’s sweeper is still an elite pitch and has been great against righties.
He’s struggled a lot against lefties this season, and I think it would make sense for the Rays to develop a changeup for his arsenal, as they’ve done successfully with several other arms this season.
Craig Kimbrel’s pitch usage this season is interesting:
74.7% Fastball
15.9% Sweeper
9% Knuckle Curve
The sweeper has been his best pitch, with a 36.4% whiff rate on it. It wouldn’t surprise me if the Rays had him increase the usage of that. Fastball 3/4 of the time when the velocity had dipped over the years doesn’t seem optimal.