Atlanta Braves: Checking in on William "Wild Bill" Contreras

Many Atlanta Braves fans were understandably sad when fan favorite William “Wild Bill” Contreras as part of the trade package that brought back Sean Murphy.

It no secret, Contreras had a very solid bat with the Atlanta Braves last year. In 97 games he had a slash of .278/.354/.506, which is good for an OPS+ of 137 (37 percent above league average). Some of his underlying metrics were good too, especially slugging.

Contreras’ expected slugging percentage (xSLG) of .479 was top 10 percent in MLB.

Is there reason to believe Contreras would regress?

With these types of numbers, no wonder he was a fan favorite and fans were understandably puzzled on why the Braves would move him a trade.

But, up to that point (2022), Contreras had a paltry 87 OPS+ (13 percent below average) in 56 games with a slash line of .225/.308/.405.

So, the question is, in his relatively small sample size of 97 games in 2022, was he due for regression over time? In other words, was he over performing?   

In short, the signs lead to yes. Although his xSLG in 2022 was elite, there are plenty of other red flags with his bat.

First, Contreras’ batting average of balls in play (BABIP) was well above league average. This is not an end all be all measurement, but when it is well above the average it is virtually guaranteed a player will regress over time. Contreras had a BABIP of .344 in 2022, and the league average was .290. His average BABIP for his career, even including last season with a .344 BABIP totaled in at .325, again showing last season he was fortunate in that arena.

If we look at his weighted On Base Average (wOBA), and expected wOBA (xwOBA), we can see a discrepancy, which indicated future drop off in performance. In 2022 he had a wOBA of .370, which was good for top 6 percent of the league. However, his xwOBA showed that the way he was swinging the bat was more in-line with a .347. Let’s not pretend like .347 is bad, it was not. The league average was .309 in 2022. However, this still shows signs of regression.

What has Contreras done so far in 2023?

It is important to point out that in small sample sizes, you will get deceiving numbers. However, when looking at metrics like expected batting average (xBA), xSLG, xwOBA, etc. you can get an idea on if it is luck based or if the player needs to make actual adjustments.

In Contreras’ case, it appears that his regression is starting and he has either made poor adjustments, or needs to make some adjustments.

Remember how in 2022 his xSLG was top 10 percent? Currently his xSLG is in the bottom 43 percent at the time of this writing. Remember, this is expected, meaning if he continues to swing the exact same way, his slugging will not get better over time. His other metrics are not much better. His xBA is bottom 41 percent, his xwOBA is bottom 35, his barrel percentage is bottom 49, his strikeout rate is bottom 35, and walk rate is bottom 38.