Why is the Offense Struggling?

This is a question I've heard asked a lot over the past few days. The first question to ask: is the offense really struggling?

I'm going to look at the splits by month to see how much the offense has really tanked during June when compared to the glory days of the first couple months when the Cubs were running roughshod over the rest of baseball.

April:
images/articles/2016-07-04/2016-04-teamoffense.png

May:
images/articles/2016-07-04/2016-05-teamoffense.png

June:
images/articles/2016-07-04/2016-06-teamoffense.png

So...that's not clear cut. April was the best month. Fewer runs were scored, but there were fewer games that month. They had a much higher wOBA and wRC+ (two good overall rate measures of offensive performance), so they were clearly better on a per game basis in the early season. But May and June are not so easy to differentiate. The team had better control of the zone and had better luck on balls in play and sequencing in May. But they hit for a lot (like 33-50% more) power in June. The runs scored pretty much balanced out perfectly between the two. The defense was significantly better in June, as well, for what it's worth.

Okay, so the June offense wasn't any worse. But what about the past couple weeks when the team has been losing?

Last Two Weeks:
images/articles/2016-07-04/2016-lasttwoweeks-teamoffense.png

That's more like it! There's the significant drop in runs we've been looking for. During this two weeks, the team only scored 59 runs compared with the 140 in June, so there's a pretty steep drop there. The wOBA and wRC+ also dropped quite a bit during that time. Let's see where that offense would rank compared to the rest of the teams in baseball for the season to date:

2016 YTD MLB Stats:
images/articles/2016-07-04/2016-season-mlb-offense.png

So that would place this really rough stretch for the Cubs in a tie for ninth in MLB (after we remove the Cubs overall season performance from the list). We could sort by wRC+, but it would be about the same story (tied for 10th). So even during this slump, the Cubs offense would rank among the top third in all of MLB by the best rate measures out there.

So why the big drop in runs? 

In a word: sequencing. They have had terrible luck with runners in scoring position during this timeframe. It's tough to find the numbers split two ways (by last 14 days and with RISP), but I do know they've had some very bad sequencing luck during this time. An easy example of that is when they were 0-17 with RISP to begin the series with the Mets. It really is that simple. There is no large cause for concern here. To illustrate why that's the case, let's dive into the player stats for each of the months.

April:
images/articles/2016-07-04/2016-04-playerstats.png

May:
images/articles/2016-07-04/2016-05-playerstats.png

June:
images/articles/2016-07-04/2016-06-playerstats.png

There's a lot to see there, but let's look one month at a time. I'm going to focus on wOBA as the primary measure here as it looks just at the overall contributions at the plate.

In April, the offense was driven by an unreal start from Dexter, Bryzzo being great, and unreal bench contributions from La Stella and Szczur. Baez also got off to a hot start in his 30 at bats and Ross was unexpectedly really good. Zobrist was just a little better than an average player and had some people bemoaning the swap of him and Castro. On the other hand, Russell and Heyward got off to slow starts and Montero and Soler were dreadful to begin the season.

In May, it was Zobrist that provded the engine for the offense. Bryant was great once again. Fowler cooled off from his unreal start, but still hit at a really high level. Rizzo had (for him) a down month, but was still above an average MLB hitter. On the other hand, the only two players who got significant at bats during the month that were a drag on performance were Heyward and (particularly) Baez. Everyone else was at least around .310 or above.

The first thing I noticed about June was how many different players there were getting AB's. Part of that has been extra inning games and a short bench driving relievers to get PA's. But the Cubs have also introduced several players to MLB during this month because of injuries to Fowler, Montero, La Stella and Soler. The player performance this month has been much more of a mixed bag. They've gotten superstar level performance from Rizzo, Bryant, Contreras and Soler (for his limited at bats). Javy was also really good this month. Almora, Russell and Heyward were all...adequate. Zobrist was okay, but well below what is expected of him. There were also some below average, but at least mediocre performances in limited at bats from Coghlan, La Stella and Ross. But Fowler, Szczur and Montero were all dreadful in June. 

The takeaway for me from all of that is that even the best players have good and bad stretches of performance. However, the Cubs have a large enough number of really talented hitters that they are not going to go into extended slumps for very long. I have full confidence that the "mini-slump" over the past couple weeks was the result of facing some good pitching and having some bad luck in sequencing their hits. That luck will change and the offense will go back to punishing the rest of baseball very soon.