A Look at the St. Louis Cardinals' Recent 7-Game Losing Streak Through the Prism of WPA

The St. Louis Cardinals went through their roughest stretch of the season during their just-concluded road trip. The Cardinals lost seven games in six days. The losing streak was the Redbirds' longest since Tony La Russa retired. It saw the club go from first place in the National League Central with the majors' best record to second place with the fourth-best winning percentage in baseball. It was a brutal stretch of games.

Twitter and the stltoday.com comments sections lit up. The crossroads of these two forums--@STLPDCommenter--really caught fire, sharing with the Twitter universe various comments from the Post-Dispatch's website. No Cardinal was safe from vitriol. Wainwright, Freese, Holliday, Beltran, Craig, Kozma--seemingly every Redbird was a whipping boy for angry fans at some point during the losing streak.

While the point of the @STLPDCommenter feed is to show that Cardinals fans really aren't all that different from any other club's fans, it nonetheless got me to thinking about who deserved the most blame for the losing streak. (Other than manager Mike Matheny, of course, who is CLEARLY not cut out to be a manager and SHOULD HAVE BEEN FIRED DURING THE OFFSEASON. #FireMatheny!)

To determine which Cardinal had the most consequential poor performance during the club's seven-game skid, we will use Win Probability Added (WPA). WPA is based off the stat Win Expectancy (WE). The Fangraphs Glossary explains WE thusly:

In the words of David Appelman, Win Expectancy (WE) is, "the percent chance a particular team will win based on the score, inning, outs, runners on base, and the run environment." These percentages are calculated using historical data, meaning if a team is losing and has a 24% win expectancy, only 24% of teams in similar situations in the past have ever come back to win.

(The Fangraphs Glossary entry for WE actually uses Game 6 of the 2011 World Series as its example of a WE chart. It's pretty cool.)

Technically, WPA should probably be titled "Win Probability Contributed" because it does not just measure how much Win Expectancy (WE) a player adds to his team's chances. WPA also measures how much WE a player subtracts from his team's chances. The Fangraphs Glossary page for WPA explains the stat as follows:

Most sabermetric statistics are context netural -- they do not consider the situation of a particular event or how some plays are more crucial to a win than others. While wOBA rates all home runs equal, we know intuitively that a home run in the third inning of a blowout is less important to that win than a home run in the bottom of the ninth inning of a close game. Win Probability Added (WPA) captures this difference by measuring how individual players affect their team's win expectancy on a per-play basis.

For example, say the Rays have a 45% chance of winning before Ben Zobrist comes to the plate. During his at-bat, Zobrist hits a home run, pushing the Rays' win expectancy [...] to 75%. That difference in win expectancy (in decimal form, +.30) from the beginning of the play to the end is Ben Zobrist's WPA for that play. If Zobrist strikes out during his next at bat and lowers his team's win expectancy by 5%, his overall WPA for the game would be +.30 - .05 = +.25, as WPA is a counting statistic and is additive.

I tallied up the Cardinals statistics during the seven-game losing streak, including WPA. I divided el Birdos by position players, starting pitchers, and relievers. The charts are pretty ugly since the Cardinals did not do much well during the losing streak. That being said, what they did consistently poorly was make outs. The offense was horrendous. The pitching let the club down in some tight games, to be sure, but the offense's poor performance was remarkable. This fact is reflected in the WPA figures.

CARDINALS POSITION PLAYERS' WPA DURING THE 7-GAME LOSING STREAK

Matt Carpenter had the most negative WPA for the Cards during the seven-game losing streak not because he made any big outs in high-leverage situations that resulted in a huge WE shift. His biggest WPA play during the streak was an -8.7% WE change against Kris Medlen in Atlanta when he flew out with a runner on first and nobody out in the top of the third inning. Carpenter's negative WPA was created by him making out after out. His slump corresponded with the club's. During the seven-game losing streak, he managed a mere .083 BA and .120 OBP.

CARDINALS STARTERS' WPA DURING THE 7-GAME LOSING STREAK

I divided the pitchers from the position players and starters from relievers because, in the WPA context, they are all different animals. While Carpenter notched 28 PAs over the losing streak, Wainwright made to starts and faced nearly twice that many opposing batsmen. Wainwright took a -10.6% hit on Mike Minor's second-inning RBI single that put the Braves up 2-1. Jayson Heyward's solo homer in the fifth that put Atlanta up 3-1 gave the wagonmaker a -11.9 WPA on the play. Wainwright fought and clawed his way to a seven-inning start, which means he made 21 outs--each one positive or neutral to St. Louis's WE. Therefore, he finished his Atlanta start with a -0.15 WPA.

This is not to pick on the staff ace. It's telling that Waino amassed a lower negative WPA in two starts that his team wound up losing than Jake Westbrook did in one start. Westbrook's five-inning start against the Braves was a brutal one. The four-run first inning against Pittsburgh was alone worth -33.1% to the Cardinals' WE. Neither Westbrook nor his teammates did much of anything to increase the Cards' WE after that fateful inning.

Miller, Kelly, and Lynn deserve little, if any, blame for the losing streak. All three pitched fairly well and left their team's WE in a better place than where it was when they started the game.

CARDINALS RELIEVERS' WPA DURING THE 7-GAME LOSING STREAK

First, I would like to point out that the Cardinals lost seven games in a row--including an extra-inning battle against their chief competition for the division title--without their closer throwing a pitch. Matheny did not call on Edward Mujica once during the slump. This is presumably because there were not any save situations. After Matheny left Mujica unused in the extra-inning loss to Pittsburgh, the manager did call on his closer to throw the ninth inning of the Cardinals' losing-streak-snapping 13-0 win over the Pirates. Mujica's WPA in that game was 0.00.

Poor Kevin Siegrist. He threw 2/3 of an inning in seven games and has the dubious distinction of posting the most negative WPA of any Cardinals pitcher during the losing streak. This is due to the fact that Siegrist gave up two walks and a subsequent walk-off single to the Pirates in the bottom of the 11th inning during the Pittsburgh doubleheader. Siegrist's 11th inning resulted in a 53.7% drop in the Cardinals' WE.

Trevor Rosenthal also finds himself amongst the club's worse in terms of WE thanks to high-leverage runs allowed. Rosenthal entered the eighth inning on July 27 in Atlanta with runners on first and second thanks to two Randy Choate walks and the game knotted up at 0-0. The fliner that Andrelton Simmons floated to left-center for a double resulted in a 31.5% hit to the Redbirds' WE. Likewise, the go-ahead single Rosenthal gave up to Russell Martin in the bottom of the eighth on July 30 in Pittsburgh dropped the St. Louis WE for that game by 29.6%. Such is the life of a late-inning reliever.

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WPA is a descriptive stat. It tells which plays and players had the biggest impact on the outcome of a game or series of games. As this chart shows, there is more than enough blame to go around for the Cardinals' recent seven-game losing streak. Lucky for Cards fans, WPA is not predictive.