Jay Jaffe: Even though both Jansen and Kimbrel now have higher strikeout rates at the 800-inning mark than Wagner (who still owns the record at 900 inning cutoff, but has just 903 IP), I think the two active guys’ ongoing declines underscore how hard it was to do what Wagner did — don’t forget, he retired coming off a 1.43 ERA season and had a 2.07 ERA from 35 onward.
That said, Jansen and Kimbrel need volume as much as they need rate stat excellence, and so long as they can maintain reasonable productivity, they’re advancing their causes. Both reached 400 saves last year in All-Star seasons, and that’s not nothing.