Who Are Baseball’s Best Relievers?
The 2017 MLB season isn’t quite over yet, but it’s never too early to start ranking the performances. Relievers are among the hardest things to rate in the game, as nobody seems to agree on the right way to do it. Below, we profile some of the best relief pitchers this season. Who would you want with the game on the line?
(All stats current through last week.)
Sabermetrics suggest that the best way to evaluate relief pitchers is to look at K%, or the percentage of batters a given arm strikes out, and K-BB%, or K% minus the percentage of batters a pitcher walks. Craig Kimbrel of the Boston Red Sox tops both metrics in 2017, striking out nearly half of the men who faced him (49.8%) on his way to a K-BB% of 44%. His 5-0 record, 1.36 ERA, and 34 Saves are sure to please traditionalists, and his underlying xFIP (1.49) suggests that factors outside of his control have had little bearing on his performance.
Kimbrel has been fantastic, but Kenley Jansen of the Los Angeles Dodgers has a compelling case if context is considered. Jansen leads all relievers in Wins Above Replacement (WAR) with 3.4, 0.1 more than Kimbrel’s mark of 3.3. His advantage grows if you use Win Probability Added (WPA), an advanced stat detailing how a given player’s actions have affected his team’s Win Expectancy. Jansen leads all relievers with a WPA of 5.16, over a full run better than Kimbrel’s 4.06. Jansen is also 5-0 with an ERA of 1.36, and his 40 Saves best Kimbrel by six. Jansen’s 42.2% K%, 39.4% K-BB%, and 1.87 xFIP are all inferior to Kimbrel’s stats though, making it challenging to choose between them. Expert handicapper and legend Jon Price knows that the key to success with baseball betting is learning as much as you can about the starting pitchers and that’s what fundamentally drives a successful team.
Kimbrel and Jansen are the top contenders, but other names may warrant consideration. Alex Colome of the Tampa Bay Rays has the most Saves with 45, but his 3.17 ERA is significantly higher than many of his contemporaries. His 4.32 xFIP also suggests that some measure of luck has been involved in his performance to date, and his 20.7% K% is below the MLB average of 21.6%. Colome is your answer if you care about nothing besides Saves, but there are better pitchers with the game on the line.
David Robertson of the New York Yankees leads all relief pitchers with nine wins, and has 14 Saves from his time with the White Sox. His 1.7 WAR, 36% K%, 27.9% K-BB%, and 2.37 WPA all fall well short of the standards set by Kimbrel and Jansen, however, so it is hard to make a case for him despite his 1.99 ERA.
Is your choice for the top RP in the game mentioned above? If not, feel free to make your best case in the comments below!
