When evaluating a hitter or pitcher’s statistical performance, the vast majority of what you need to know comes from the following rate data – strikeouts, walks, popups, line drives, hard and weak flyballs, and hard and weak groundballs. Put some of those on the good side of the ledger, the rest on the bad, and pretty quickly one has a feel for the present ability, and along with scouting data, the future projection of the player. Today, let’s focus on strikeouts and walks, and on quantifying their overall impact on hitters’ offensive production. How much must a hitter do to compensate for poor K and BB rates, and much additional margin for error is provided by strong K and BB rates.
Our control group will be 34 position players who have changed clubs this offseason and logged substantial playing time in 2013. First, let’s take a look at these players’ 2013 strikeout/walk data expressed in a few different ways.
|Last||First||K||BB||K %||BB %||K %:100||BB%:100||K PCTILE||BB PCTILE||GROUP|
The table above lists each player’s raw K and BB totals, their K and BB rates, those rates scaled to MLB average of 100, and expressed in overall percentile rank within the MLB regular player population. The players are also placed in groups (far right column) as follows: Group 1 = K rate below MLB average, BB rate above MLB average; Group 2 = K and BB rates below MLB average; Group 3 = K and BB rates above MLB average, and Group 4 = K rate above MLB average, BB rate below MLB average. This table alone, however, tells us a limited amount about each player’s offensive ability. Let’s fill in the picture a little more by adding performance on balls put in play (including homers) for each player, and then quantify the impact of the K and BB data on each hitter, and each group of hitter.
|Last||First||BIP AVG||BIP SLG||BIP RUN||BIP R:100||TOT AVG||TOT OBP||TOT SLG||TOT RUN||TOT R:100||GROUP|
An editorial comment – it’s always bugged me that HR are excluded from BABIP calculations. Not all HR are created equal – a ball that goes over the fence and is excluded from BABIP for one hitter, goes into a glove and is included in BABIP – negatively – for another. End of editorial. Also, for the purposes of this exercise, the BIP and Total (including K and BB) run values are being calculated and scaled to the MLB average ERA as follows: the square of ((1.7 * Player OBP + Player SLG)/(1.7 * MLB OBP + MLB SLG)) * MLB Avg ERA. Also, I am arbitrarily excluding HBP from the above OBP calculations, and including SH and SF as ordinary outs for the purpose of this exercise. The estimated run values excluding and including the K/BB data are scaled to 100 in the 4th and 9th columns above. They are not adjusted for park factors.
Based on performance on batted balls alone, Jarrod Saltalamacchia (with plenty of help from the Green Monster) and Marlon Byrd (with some help from the surprisingly compliant Citi Field LF/LCF area) are the most productive, with the somewhat unlucky David Murphy and groundball machine Norichika Aoki bringing up the rear. The average MLB player’s run value scaled to ERA is decreased by 1.03 (from 4.90 to 3.87) by the addition of the K/BB data – the 34 players above saw their run values decrease by an average of 1.22. Now let’s look at the results by K/BB group.
|GROUP #||AVG -RUN||+/- R100|
|- K, + BB||1||0.49||13.6|
|- K, – BB||2||0.81||4.8|
|+ K, + BB||3||1.84||-16.2|
|+ K, – BB||4||2.24||-25.2|
The table above shows how significantly a high K rate, especially, negatively impacts a player’s ability to achieve a high level of production. Hitters in Group 3 – higher than average K rate, higher than average BB rate – see their run value scaled to 100 fall by an average of 16.2 basis points from their run value based on batted balls alone. The Group 4 hitters – higher than average K rate, lower than average BB rate – are hit even harder, by an average of 25.2 basis points. This is the dynamic that drives a Mark Trumbo – a Group 4 player with a batted ball run value of 128, into a league average-ish 102 guy once K and BB are added in. It makes someone with an acceptable batted ball profile like JP Arencibia (Group 4 – 93) into a sub-replacement level offensive player (64). It makes someone like Marlon Byrd (Group 4 – off-the-charts 169 on batted balls) utterly reliant on such a level of batted ball authority because of the huge minus contributed by his poor K and BB rates. Conversely, players with relatively unimposing batted ball profiles like Norichika Aoki (Group 1 – 72) and Ian Kinsler (82) whose Group 1 K/BB profiles make them league average-ish offensive players with relative run values of 100 and 105 once K and BB are taken into account. In a nutshell, if you’re going to strike out a lot, you had better punish the baseball consistently when you do make contact.
The tables above give us more reasons why a hitter like Robinson Cano is as good as he is. Based on his batted ball performance alone, five hitters above rank above his relative run value mark of 130. His solid Group 1 K/BB performance bumps him way up to 150 in terms of overall relative run value, the best among this group. Cano isn’t overly reliant on impact batted ball authority, or on impact K or BB rates. He’s simply good at all of these aspects of hitting, and while each of his abilities will deteriorate over time, he’s unlikely to suffer a sudden plummet because of a breakdown in any single aspect of his game – his other skills will keep afloat longer than a player overly reliant on one single component.
It is self-evident that K and BB rates impact the production of position players and pitchers, but the above helps quantify that impact. A very similar analysis for pitchers can and will be prepared in an upcoming post. Obviously, there are many angles not taken into account here – park factors, the impact of player speed on performance on balls in play, luck, etc. – but this much is clear. Maintaining solid K and BB rates do not alone make a hitter good or bad, but doing so clearly enhances the margin for error a hitter possesses with regard to the authority with which he puts the ball in play. Ian Kinsler’s batted ball authority has declined in the recent past – but his K and BB rates have allowed him to at least continue resembling Ian Kinsler – for now.
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