So he'll be at about 191 saves at the end of this season. At the same age, Mariano Rivera had 5 saves. Rivera ended up with 652, including getting 126 after the age of 40.
I hadn't realized that River was 27 when he officially took over the closer role in NY. Even with that incredible head start, Kimbrel would have to average 45 saves for the next 10+ years to surpass Rivera.