ERA Equivalent WHIP (or Why Yusei Kikuchi is Unrosterable)
Every week, I look through my rostered pitchers noting the worst ones and churn them out next week. This week, the Yusei Kikuchi stood out. Someone with a 3.06 ERA and his ERA estimators around 4.50. It was his ERA estimators throwing red flags, but I have other pitchers worse. It was his 1.52 WHIP, third worst among qualified starters behind Kyle Freeland (1.63) and Jack Kochanowicz (1.56). With WHIP being its own Roto category, it has as much weight as ERA but ERA is the mentioned multiple times more often than WHIP. I’m just going to create a simple WHIP to ERA conversion to put both on the same scale.
To get the conversion equation, I used the overall rankings for the NFBC’s Main Event (15 team) and Online Championship (12 team). With them, I ranked the WHIP and ERA values separately. I removed the the first and last 10% of values because the change for them isn’t linear.
With the tails removed and plotted the best remaining WHIP with the best remaining ERA. I did that for each one. Here are the plotted results.
The correlation is nearly perfect, so the correlation equations can be used to convert a WHIP to an ERA equivalent. Here is conversion table.
| WHIP | ME Eqiv ERA | OC Eqiv ERA |
|---|---|---|
| 0.70 | 0.48 | 0.52 |
| 0.80 | 1.09 | 1.12 |
| 0.90 | 1.70 | 1.72 |
| 1.00 | 2.31 | 2.33 |
| 1.10 | 2.92 | 2.93 |
| 1.20 | 3.53 | 3.53 |
| 1.30 | 4.14 | 4.13 |
| 1.40 | 4.75 | 4.73 |
| 1.50 | 5.36 | 5.33 |
| 1.60 | 5.97 | 5.94 |
| 1.70 | 6.58 | 6.54 |
| 1.80 | 7.19 | 7.14 |
| 1.90 | 7.80 | 7.74 |
| 2.00 | 8.41 | 8.34 |
The results for the two league types are close so I’ll only use the Main Event information going forward. Besides the above table, I have created a public Google Sheet (copy by going to File -> Make a Copy) where a WHIP can be entered and an equivalent ERA is spit out.
Kikuchi’s 1.52 WHIP would be equivalent to a ~5.50 ERA. No one is starting/rostering a pitcher with a 5.50 ERA this deep into the season. The high WHIP can’t be ignored and I’m likely to move on where I can find decent options.
Besides Kikuchi, Here are the qualified pitchers who have a WHIP that does as much ratio damage as a 4.50 or worse ERA.
| Name | ERA | WHIP | equivalent ERA | NFBC Main Event Roster% |
|---|---|---|---|---|
| Kyle Freeland | 5.72 | 1.63 | 6.15 | 4% |
| Jack Kochanowicz | 5.34 | 1.56 | 5.72 | 4% |
| Yusei Kikuchi | 3.06 | 1.52 | 5.48 | 98% |
| José Soriano | 3.41 | 1.51 | 5.42 | 98% |
| Randy Vásquez | 3.99 | 1.47 | 5.18 | 42% |
| Gavin Williams | 3.79 | 1.45 | 5.05 | 100% |
| Luis L. Ortiz | 4.40 | 1.43 | 4.93 | 91% |
| Max Meyer | 4.73 | 1.42 | 4.87 | 100% |
| Sean Burke | 4.20 | 1.42 | 4.87 | 28% |
| Jonathan Cannon | 4.66 | 1.40 | 4.75 | 21% |
| Michael Lorenzen | 4.33 | 1.40 | 4.75 | 98% |
| Zac Gallen | 5.54 | 1.40 | 4.75 | 100% |
| Dean Kremer | 4.70 | 1.39 | 4.69 | 81% |
| Jeffrey Springs | 4.72 | 1.38 | 4.63 | 97% |
| Shane Baz | 4.92 | 1.38 | 4.63 | 100% |
| Andre Pallante | 4.23 | 1.36 | 4.50 | 86% |
| Chris Bassitt | 3.80 | 1.36 | 4.50 | 97% |
Gavin Williams and José Soriano have been devastating managers’ in the WHIP category but it doesn’t seem as bad with sub-4.00 ERA.
WHIP is probably one of the most misunderstood categories and hopefully I made it easier to understand an expectable value.
Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.
Excellent way to illustrate how WHIP is greatly overlooked. Made me go look at my team. He isn’t qualified but Roupp’s 1.38 is far less helpful than his 3.18 ERA.
Agreed. On Roupp watch the trend lines as his recent WHIP from May 1 on is 0.95, 1.75, 1.17, 1.17, 1.00, and 1.00. One bad blowup in Detroit but fairly strong performance otherwise against mostly good teams. He has walked at least two batters in each of the last 4 and that’s his big issue (most of his early year blowups were 3 walk+ affairs).
I think he likely delivers better than 1.38 going forward because I like his talent.
One other thing I’ll note. My leagues are mainly points leagues so WHIP is not directly relevant but correlates to value. It is the most volatile and most tightly bunched ratio stat by a fair amount. For example in a 12 team league I play the standard deviation is 0.05 with only three teams more than 1 standard deviation away from average in either direction. The margins get really fine so blow ups can really impact this stat
Fair point and FWIW, I have no intention of dumping Roupp since I like him as a young guy on the rise.