Year in review: A (very) brief retrospective

A few weeks ago, I took a look at what the 2016 Mariners offense could like based on their performance in the second half. In that article, I used some of the data from my series previews to show the progression of the Mariners’ offense through the year. I loved the story that graph told; a decent offense to start the year, followed by a huge dip in June and July, and then steady growth through the end of the year. Well, the offense was only half of the story. How did the Mariners’ pitching staff progress as the season wore on?

First, here’s the graph showing the team’s wRC+ starting from late April through the end of the season:

And here's the graph showing runs scored per game and team wOBA with the league average (in grey) alongside them:

I won’t rehash what was already said in that other article. In short, the Mariners offense in the second half was one of the best in the AL and much of that was driven by players who are under team control next year.

The Mariners pitching staff had an up-and-down journey this season. Taken straight from each series preview, here’s a graph showing the Mariners’ team FIP-, split into starting rotation (navy blue) and bullpen (yellow):

There was much less volatility in the pitching staff’s performance. For the majority of the year, the staff was below league average with a few "dips" towards respectability. Unfortunately, there’s a stretch in August where the pitching staff really fell apart, beginning with that terrible series in Boston.

In fact, all of August was a pretty rough month for the pitching staff; as a team, the Mariners allowed the most runs in the AL, and it wasn’t even close. Here’s a graph showing runs allowed per game and team FIP with the league average for each metric in grey (remember, for pitching stats, below average is better):

April was actually one of the better months for the Mariners’ pitching staff. Their FIP was third best in the AL and they were a bit unlucky to have so many runs scored against them. That flipped in May when their FIP ballooned to the worst mark in the AL but their runs allowed actually dropped to fifth best in the league. June was another good month but this coincided with the offense cratering, which led to another month with a losing record. July and August were absolutely terrible and only the offense coming to life saved the team from digging themselves into a deep, deep hole.

Luckily, the team ended the year with a great month of pitching in September; their FIP was second best in the AL and the team allowed the third fewest runs in the last month of play. The team was firing on all cylinders in September and was close to making things interesting in the last few weeks of the season. We can’t just extrapolate one month’s performance directly to next year, but it’s good to see that, given a month of play where everything is going right, they can compete with the best of the American League.