His detractors talk about his winning percentage. While it was not dominant, the fact that he went 283-237 still bode for a .544 winning percentage. In his first 18 full seasons, Kaat had an average of 14.3 wins per season. Early on in the 1979 season, he was sold to the Yankees, who used him primarily as a relief pitcher. The following season, just as early on, he was sold to the St Louis Cardinals where he made 14 starts, but also relieved in 28 games for the Cardinals. He followed that up with two very good seasons, pitching primarily out of the bullpen. It culminated with a 1982 World Series Championship, the first and only of Kaat's MLB career. Did he have to convert to a reliever? Did the change in fact save his career? Because if he could not have been an effective starting pitcher any more, the argument is useless.
Kaat's last effective season as a starter came in 1976 for the Phillies, his first season there. He was 12-14, 3.48 in 38 games, 35 starts. He threw 227 2/3 innings that season, but the major disparity was his Ks to IP. He struck out just 83 batters, for a 3.3 Ks/ 9 IP. Kaat would have his worst season in 1977, going 6-11, 5.37 in 35 games, 27 starts. He rebounded with a respectable 8-5, 4.10 in 26 games, 24 starts. But his Ks/ 9 IP had dipped to 3.1. Despite being part of three straight NL East Champions with the Phillies, he did not pitch in one postseason game for them.
One of his strengths was his knowledge of the art of pitching. While he did K over 200 batters twice during his time with the Twins, Kaat was one of the better thinkers on the mound. He knew what to throw in which count and how to keep the batter off balance. Something that was imperative for a pitcher who was losing some of his velocity. Now a days, we can think about Jamie Moyer and his ability to get hitters out as he managed to stick in the majors until age 49. Kaat did not have much left as a starter. The fact that he made the transition to a relief pitcher saved his career. It is silly to think he could have had the same success as he did in years prior being a starting pitcher.
But, had he stuck it out for longer as a starting pitcher could he have stayed in a team's rotation? What if the Yankees had used him as a starter? Playing with hypothetical numbers allow me to say that if Kaat had pitched 4 more seasons as a starting pitcher, he could have added 56 more wins to his 1978 total of 261 wins. 317 career wins is an automatic Hall of Fame nomination.
For the reasons I stated earlier, the likeliness of Jim Kaat sustaining anymore success as a starting pitcher were probably miniscule. But if there was a pitcher that could do it. I'd bet on Kaat. From 1979 to Kaat's final days with the Cardinals (he was released on 7/6/1983), he won a total of 22 games. Could he have averaged 10 wins a season from 1979-1982? Because that would have put him at 301. Kaat's Hall case is one of the interesting ones, one that Tommy John and for a while, Bert Blyleven, had to deal with. Perhaps there will be a day where both Kaat and John get the recognition Blyleven got. No doubt Kaat was one of the better pitchers of his time. Pitching on those staffs with the Twins, he joined Jim Perry, Mudcat Grant, Luis Tiant and others in one of the best pitching staffs in all of baseball. Hopefully the next time the expansion committee gets together in the Veterans wing of the Hall voting, maybe they will take another look at Kaat, who has received 54% of the Veterans Committee vote in 2005 and 63% in 2007. The highest percentage of the vote Kaat ever received when eligible for the BBWAA vote, was 29.6% in 1993.