Batting average is not a completely useless statistic. That is something you might have heard among those who favor advanced statistics. However, it is not true. Batting average tells us something: that if you remove walks, hit-by-pitches, and sacrifices, it tells you the percentage of times the hitter reached safely. That can be useful information, but only if you lack other information. When you compare batting average to on-base percentage and add in slugging, ISO, and wRC+, then batting average loses its use. The Cardinals have several players with very poor batting averages early in the season. It's safe to ignore batting average and do not assume a player is struggling simply because their average seems weak.
So far this season, the Cardinals have a good batting average at .276 before last night, ranking third in all of baseball. So far this season, the top four teams in batting average are in the top 10 of runs scored and are also among the top five teams when i comes to wRC+. That might lead to conclusions that batting average is in fact important, but we have yet to compare it to any other statistics.
A few simple examples. Here are the top 5 teams in batting average along with their ranks in runs scored and wRC+:
|Batting Average Rank||Runs Scored Rank||wRC+ rank|
Not too bad. Now let's compare it to on-base percentage.
|OBP Rank||Runs Scored Rank||wRC+ Rank|
That was just a simple example, but we know that on-base percentage has a higher correlation with runs scored than batting average does. Not make an out is the most important thing a batter can do. Much of this might not be new for many of you, but batting average still appears on every single game broadcast and it might be easy to look at a player's batting average and assume they are struggling offensively. That might not be the case.
The current batting average MLB-wide for non-pitchers is .252. I mention this because the Cardinals have seven players getting at least semi-regular playing time with a batting average below that mark. (I updated the stats from last night. Piscotty is now above league average, but I will keep him in the list). Those players are as follows:
|BA||Diff from Lg Avg|
If that is the statistic you are seeing, you might think all of those players are not producing on offense. Piscotty and Adams are close to average, but everybody else is well below with Moss way down there. Batting average does not take walks or power into account, and those are two important aspects of hitting.
First, let's look at on-base percentage. The MLB number for non-pitchers is .322. Here is where those same players sit relative to league average for OBP:
|OBP||Diff from Lg Avg|
Adding walks to the equation shows a very different picture. Since OBP is a better indicator of runs scored, it is a more important stat to pay attention to if you believe a player is struggling. Carpenter, Grichuk, Piscotty, and Holliday are not struggling at all. Before we relegate Moss, Wong and Adams to struggling status, we should take a look at power, too. There are a few ways to determine power. ISO (Slugging minus batting average) is the best way to look at just power, but for in attempting to get at overall effectiveness, we will add slugging percentage, which includes batting average as an element. League average ISO is .158 and slugging is .410.
|ISO||Diff from Lg Avg||SLG||Diff from Lg Avg|
Kolten Wong does not have a single extra base hit this season. He has yet to deliver. Matt Adams is bringing below average power, but everybody else is above league average. Brandon Moss, whose average is more than 70 points below Adams has a higher OBP and significantly more power.
These stats are not presented with any predictive value or comments on their sustainability. They are presented more to determine whether a player with a bad batting average is actually struggling to contribute on offense. As the stats above show, Carpenter, Grichuk, Piscotty, and Holliday have delivered positive contributions while Wong and Adams are in the negative. Moss is sort of caught in the middle. The single best statistic to use when you want to consider the contribution at the plate (without base-running) is wRC+. wRC+ considers all aspects of a player's production and then uses the ballpark and league average to come up with an overall number relative to league average (non-pitchers) with 100 set as average.
Here are the numbers for the players above:
The Cardinals have been very good this year on offense because they have so few players who are actually struggling. Kolten Wong has had a tough go of it so far, and Adams has been bad, but he also has few plate appearances. Moss isn't playing well, but he is not hitting poorly either. The players expected to produce are producing, and players like Aledmys Diaz (252 wRC+), Jeremy Hazelbaker (168), Jedd Gyorko (141), and Yadier Molina (124) have been pleasant surprises so far. If someone wants to point to batting average to say a player is struggling, they might not necessarily be wrong, but we need more information to make that determination.
*When originally published, stats were through Sunday. They have now been updated to reflect last night's game.