Adam Wainwright entered August as one of the best pitchers in baseball, with a 1.92 ERA, and having recently started the All Star Game for the National League. He looked to be the only NL pitcher capable of competing with Clayton Kershaw for NL Cy Young. Between his start on opening day and July 31, Wainwright threw 150 innings, allowing only 32 earned runs; he was controlling the zone effectively, striking out 122 and walking only 34 ----- 3.6 Ks for every one BB. He was cruising along until the dog-days of August hit, and Wainwright seemingly looked like an entirely different pitcher. In 6 starts last month, he allowed 22 ER in only 38 innings, and the K:BB dropped to 2.5. After starting the season giving up 2 or fewer runs in 18 out of his first 21 starts, he gave up at least 2 in 6 out of 7 August & September starts. While Brewers and Pirates fans licked their chops, hoping the dominant Wainwright was left in the distance, it was far from the truth. In essence, Wainwright was the victim of ill-timed random variation in performance and regression where he was outperforming his career numbers.

Looking at Wainwright's stats through the earlier part of the year (through July 31) there is evidence that we all should have expected some regression. A few clues to this impending regression can be found in left-on-base percentage, opponents batting average on balls in play, and expected field independent pitching numbers versus actual earned run average numbers. During this stretch, Wainwright stranded 83% of runners who reached base; a number 10% higher than league average, and 8% higher than his career average. Wainwright was also allowing a stingy.260 BABIP, 35 point lower than league average of .295. While it may not be surprising that a dominant pitcher like Wainwright has the ability to strand runners and limit hard contact at a better clip than other pitchers, he was also outperforming his career .292 BABIP by 32 points.

Waino did not allow a HR in June or July, which is utterly fantastic. It provided Wainwright with a 2.35 ERA and a 2.78 FIP, much in line with the eye-test of his dominance. In the earlier part of the year, he was pitching to an entirely unsustainable 3.2% HR/FB rate. Normalizing his HR/FB ratio to league average gave Wainwright an xFIP of 3.74 ----- over a full run difference. This isn't to say that he would start giving up a significant amount of long balls, but it absolutely implies he would be giving up more than he had been. Adding the six home runs given up in August and September, Wainwright's HR/FB percentage increased to 5.6%. If the HRs were more evenly distributed throughout the earlier months, rather than all within a 4 week span, we barely would have noticed the significant difference in his numbers, and they still would have been viewed as fantastic. Due to the random variation of them all happening in a four week span, people took notice, and started to question what may have been wrong.

Adam Wainwright is truly having an excellent year, and a few bumps in the road in August should not make us think otherwise. Random variation, the sequencing of home runs and anticipated regression of peripheral numbers still show him as an ace. As it happened, through random variation in data, his poor games were bunched together rather than spread across the entire summer. Although it may be tempting to blame fatigue or age on Wainwright's late summer ‘crash' his overall numbers are very much in line with what he has done in the past. Even accounting for a rest of season ERA of 3.5, he would still finish with a sub-3 ERA. The excellent innings logged at the start of the year are not going anywhere, we just can't continue to expect the 2.35 ERA we saw at the start of the season to continue for the entirety of the season.

Looking at his entire body of work, and the incredible number of effective innings Wainwright has give the Cardinals throughout his career, it would foolish to think he could not deliver in September and October. Since coming back from a lost 2011 season due to Tommy John Surgery, Waino has thrown 198, 241 and 203 innings in each of the past three seasons. Although the start of his 2014 initially looked like a potential career year for the 32 year old Wainwright, he's on pace to have a year more aligned with his 4 WAR 2012 than his 6.3 WAR 2013. He will probably end up somewhere in the middle, but if I'm facing the Cardinals in a short series, I'd be afraid. Very afraid.