Is Yoenis Cespedes' Impact on the A's Overestimated?

And other stats-filled observations in our weekly Oakland stat brief from A's columnist Matt Keith.

Like much of the first month, the past week has been a bit of a roller coaster for the A's. First, they extended an ugly slide with a couple of losses to Baltimore. Then Yoenis Cespedes returned from injury and they won three straight. An exhilarating 19 inning comeback win turned out to be costly in that it sent Coco Crisp and Brett Anderson to the DL.

Pitching Consistent... In a Bad Way

In the midst of this 3-3 week that had as many highs as lows, one thing has been fairly consistent - the A's pitching continues to stink. After allowing six or more runs four times in the last week, the team ERA has spiked to 4.33, 12th in the American League. With only 84 walks, the pitching staff has managed to keep opponents on base percentage to a respectable .318, below the AL average. But it has also allowed a dismal 273 hits, many of which have been extra base knocks as evidenced by a .417 slugging percentage allowed.

I pointed out last week that starting pitching was primarily to blame, and that trend has continued as the rotation's ERA now sits at a somewhat sickening 5.14. But I would be remiss if I failed to point out that the play in the field hasn't exactly helped.

Even if we ignore the 18 errors that rank the team 12th in the AL (since they don't affect ERA), there are disturbing stats. Oakland has turned just 21 double plays all year. Though part of that can be pinned on a 0.67 ground ball to fly ball ratio, even ground ball pitchers aren't getting double plays out of this defense. Brett Anderson has a career high 1.72 GB/FB ratio this year and a career low 10 percent double play percentage. Is part of that his fault for not inducing easy grounders at opportune moments? Undoubtedly. But a team with a combined defensive WAR of -1.3 isn't helping.

Cespedes' Impact Overblown?

As far as the offense goes, much has been made of Yoenis Cespedes' impact on the A's fate. Without him in the lineup, the team has gone 5-10. With him playing, they're 11-3 and averaging nearly three more runs per game than when he's on the bench.

Those figures certainly seem to indicate that Cespedes is the key cog in Oakland's wheel. That is likely true, but the above numbers probably also overestimate the slugger's impact on the offense.

Cespedes has been on the field only twice this year against a team that currently has a winning record (in fairness both were wins). Of the 14 games that he's played, 12 have come against the Angels, Astros and Mariners, who have a combined record of 31-56 and rank 13th, 15th, and 11th respectively in the AL in runs allowed.

Meanwhile, eight of the 15 games Cespedes has missed came against the Orioles, Tigers and Red Sox, whose combined record is 53-31 and two of whom rank in the top five in the AL for fewest runs allowed.

The bottom line is that Cespedes stint on the DL coincided with the toughest part of the A's schedule. While the team is certainly much better off with his bat in the lineup, it's extremely, extremely doubtful that he would have been worth three additional runs per game during the A's losing streak. We'll start to find out exactly how valuable he is against better opposition this weekend against the Yankees.

The first month of the season went well for the A's in many respects. They dominated in-division games to the tune of a 13-3 record, and the offense has been superb so far. Yet they also have work to do if they want a repeat playoff appearance. They've specialized in beating up bad teams while losing to good ones. Routinely struggling against other playoff contenders won't cut it. The slumping young starting pitchers also have to prove that April was an outlier month, and that last year's rookie performances were not the aberration.