I originally intended to write a story about timing, comparing when Joe Nathan and Francisco Rodriguez’s each landed on the Hall of Fame ballot. When Francisco Rodriguez debuted last year I felt his timing was better than Joe Nathan’s who debuted on Barry Bonds, Roger Clemens and Curt Schilling’s last year on the ballot (and each took roughly 60% of the vote each). In short I felt that Nathan’s timing was poor while K-Rod’s timing was great. Last year, when Rodriguez debuted, fewer players received at least 5% of the vote, and more space was available to consider borderline candidates, while far less space was open to Joe Nathan.
But looking at the two I realize now that my original hypothesis stems from my personal bias that these two players would be considered similarly. From an advanced statistical standpoint you can argue the two were similar, but I suspect the voters saw the two as quite different. After looking at K-Rod long and hard last year, I think I may have miss-judged his case, and he’s actually a much stronger candidate than I originally believed.
Grading Relievers is Hard
Judging how good a reliever is frankly frustrating for me. Relievers may appear in more games than starters but, since they throw far fewer innings, individual seasons can prove noisy. Take Emmanuel Clase’s season this year: he led the league in saves (for the second season in a row), but overall was far less effective (he also led the league in blown saves). In fact, there really is not that huge of a correlation between saves and effectiveness. The only other Cleveland reliever to lead the league in saves is Joe Borowski, who also holds the distinction for the only reliever to ever lead the league in saves with an ERA over 5.
When the primary statistic typically defining a reliever (saves) is so noisy: trying to distinguish between ostensibly similar players is hard. If we use saves, for instance, the Francisco Rodriguez v Joe Nathan comparison appears a little silly:
Francisco Rodriguez
437 Career Saves, All-Time Single Season Saves Record of 62, and led the league in Saves three times
Joe Nathan
377 Career Saves, never led the league in Saves, but did lead the league in Games Finished once
From that perspective Rodriguez is not only the better candidate: he’s the obvious candidate. Considering both pitched during about the same time frame and in the same league it’s telling that K-Rod more frequently led the league in saves. He also set the single season Saves record, which still stands. Hall of Fame voters have typically used Saves as their general barometer of grading relievers too.
Eight relievers have been inducted into the Hall of Fame, here they are in order of their career saves total:
Mariano Rivera 652 (1st)
Trevor Hoffman 601 (2nd)
Lee Smith 478 (3rd)
Dennis Eckersley 390 (9th)
Rollie Fingers 341 (15th)
Goose Gossage 310 (27th)
Bruce Sutter 300 (30th)
Hoyt Wilhelm 228 (43rd)
If Billy Wagner gets inducted this year, as is likely, the Hall will add the 6th place reliever in saves as well. Two active players, Kenley Jansen and Craig Kimbrel, are 7th and 8th (and likely to earn induction eventually), which leaves Francisco Rodriguez at 4th place conspicuously absent.
Furthermore: the rankings of Eckersley, Fingers, Gossage and Sutter are misleading. When Eckersley retired he ranked 3rd in saves all time, while Fingers, Smith & Wilhelm each held the career saves record when they retired. Overall: saves have played an integral part of why relievers earned induction into the Hall of Fame.
Which brings me back to Francsico Rodriguez: from a Saves perspective: his case is excellent, if not quite air tight. He led the league in saves more frequently than Eck or Hoffman (or, for that matter, Billy Wagner) and also holds the single season record. His career total ranks fourth all time, although this does appear tenuous at best: if Kimbrel and Jansen stay healthy for another year both appear likely to pass him next year.
So the case is closed right?
Gauging Effectiveness
In my mind: no. Saves are a flawed statistic in my view; they remind me in many ways of RBIs. A reliever cannot get a save unless his team hands him a lead, so you can easily have a more effective reliever post fewer saves simply due to opportunities. You can also have a bad reliever notch a bunch of meaningless saves (see Borowski, and Clase’s 2023). So while K-Rod’s save total is impressive: I do not think that should be the beginning or the end of our analysis.
The biggest two things I like to see in a reliever are a high strikeout rate, and a low ERA. The job of a reliever is to stop the bleeding, or hold tight leads, making someone who keeps the ball in the park a premium. From this metric K-Rod looks pretty good with a career SO/9 of 10.5; for reference Mariano Rivera’s is 8.2 (and Nolan Ryan’s is 9.5). Now, that by itself is not historic: fellow ballot mate Billy Wagner holds the record among retired relievers with a minimum of 800 IP at 11.9, and the active twosome of Kenley Jansen and Craig Kimbrel both exceed even Wagner’s K-rate.
Granted, we must consider that more batters strikeout now than they did when Rodriguez and Wagner pitched. Fangraphs created a statistic called K%+ which measures how much higher a pitcher’s strikeout rate is compared to the league average. Using this metric Francisco Rodriguez ranks 5th all time behind Billy Wagner, Mark Clear, Dennis Eckersley and Tom Gordon. By this metric: Francisco Rodriguez does not just look worthy, he is almost historic.
On the run prevention side Rodriguez also looks quite good. His career ERA of 2.86 does not necessarily scream “Hall of Famer” given that some starting pitchers posted career ERAs that low. However, when we take into consideration the era in which Francisco played his ERA+ (a measure comparing a pitcher’s ERA to the league average) he is a more robust 148. An ERA+ of 148 looks quite good compared to other relievers in the Hall of Fame. Here’s that same list of pitchers above by ERA+ (I will also include some other pitchers in consideration):
Mariano Rivera 202
Billy Wagner 187
Craig Kimbrel 171
Kenley Jansen 157
Joe Nathan 151
Francisco Rodriguez 148
Hoyt Wilhelm 147
Trevor Hoffman 141
Bruce Sutter 136
Lee Smith 132
Goose Gossage 126
Rollie Fingers 120
Dennis Eckersley 116
Again, we can see Rodriguez fits right into this grouping as well.
Overall, when we consider everything: we can see why Rodriguez is such a compelling candidate. Compared to his contemporaries: he was a strikeout machine (granted, not quite as much as Billy Wagner). While his save total is not in and of itself historic: it ranks quite highly and still holds up even with some modern relievers set to pass him, and he holds the single season Saves record.
Returning to the Joe Nathan Comparison
Now, why did I at first consider this a question of timing? I looked at Jay Jaffe’s JAWS statistics for relievers, and by this metric Joe Nathan looks better than Francisco Rodriguez. According to Reliever JAWS: Joe Nathan is the 7th best reliever of all time behind six Hall of Famers and Billy Wagner (who is himself likely entering the Hall of Fame). Francisco Rodriguez ranks 12th. What separates the two? To shorten a lengthy explanation: Joe Nathan was among the best in baseball history in high leverage situations.
Jay Jaffe calculated this by combining two statistics: Wins Probability Added (WPA) and Levering Index (LI). WPA measures how much a player added (or hurt) to his teams probability of winning a game, while LI measures how crucial a given situation was to winning a game. For example, Rajai Davis’s home run off Aroldis Chapman in Game 7 of the World Series was a WPA of 0.39 meaning he increased Cleveland’s chances of winning the game by 39%, and the LI of that at-bat was 1.9, making it a high leverage situation. Combining these two measures Jaffe reckons Joe Nathan was 6th all time, while K-Rod was only 12th.
For me, if you exclude saves, it’s really difficult to differentiate between relievers. How much would I truly prefer Francisco Rodriguez over Joe Nathan? I can see an argument for both, but not for one over the other: their regular season statistics are simply too close. Here are their overall major stats:
Francisco Rodriguez
2.86 ERA (148 ERA+) in 976 IP, 1,142 SO-389 BB, 10.5 SO/9, 3.6 BB/9, 1.155 WHIP
Joe Nathan
2.87 ERA (151 ERA+) in 932.1 IP, 976 SO-344 BB, 9.5 SO/9, 3.4 BB/9, 1.120 WHIP
It’s a head scratcher: Nathan fell off the ballot with little fanfare, while Francisco Rodriguez’s 10.6% was similar to Billy Wagner’s debut, and he is on the cusp of induction.
Postseason Glory?
There is one other piece of information we can examine to differentiate relievers: the postseason. Mariano Rivera was a postseason legend with a career postseason ERA under 1. Joe Nathan, Billy Wagner and Trevor Hoffman were all postseason goats with Nathan’s career postseason ERA over 8 (in limited opportunities) and Wagner’s over 10 (again in limited opportunities). Meanwhile: Francisco Rodriguez posted a fairly sterling 2.96 ERA in the postseason, including a vital performance in the 2002 World Series striking out 13 batters in 8 and ⅔ innings for the Angels and posted 13 consecutive scoreless innings that postseason.
While this certainly does not match the record of Mariano Rivera (and who could?) it’s also much better than most other relievers being considered for the Hall of Fame. It’s also a better record than Craig Kimbrel (who has been infamously shaky in the postseason) and Kenley Jansen who was terrible in the 2020 World Series he won with the Dodgers.
I am not willing to lean too heavily into Francisco Rodriguez’s limited postseason success, but I think it is something to at least consider.
Outlook
Personally if I were king I would have inducted Mariano Rivera into the Hall of Fame and no other relievers. No Goose Gossage, no Trevor Hoffman, no Rollie Fingers (or Bruce Sutter) and no Billy Wagner. That would also mean no Francisco Rodriguez. But this is not the world we live in, and in a game more thoroughly dominated by relievers than ever before I am unsure whether that stance could have lasted into the modern era.
In the world we live in I think K-Rod is every bit as good a candidate as Lee Smith, if not better, and certainly almost as good as Billy Wagner. I would induct both into the Hall and Joe Nathan if given the opportunity. I do think as time goes on we will struggle to differentiate between the game's best relievers, but there are still only a few who can reach the lofty heights we saw Rodriguez reach during his career.
-Benjamin, J