Ranking the Chicago Cubs’ Bullpen, Checking In on Batted Ball Rates and Pitch Selection

The first two days of the Cubs’ four-game set against the Dodgers were representative of what the common bullpen experience can be like, as the team ran the spectrum in the span of 48 hours.

In the team’s Game 1 win, the only thing better than the match-ups against a lefty heavy Dodgers lineup was the execution by Travis Wood and his teammates in throwing seven perfect relief innings. On the other hand, the Game 2 loss exemplified how things could go wrong even if match-ups provide a platoon advantage.

The Cubs are one-third of the way through the season and it is safe to say the bullpen’s year (as a collective) has been a weird one. Some of it has been good, but probably not as good as one would like. Some has been bad, which suggests room for improvement.

Let’s check in on the bullpen stats, heading into the weekend:

Nothing sums up the state of the bullpen like these four rankings. The team’s 3.15 ERA and 3.80 xFIP rank in the top 10. And while top-10 rankings are good, ranking near the middle in fWAR and FIP leaves much to be desired. (Of course, given how deep Cubs starters have generally been pitching, the Cubs’ relievers have had a little less opportunity to accumulate WAR.)[adinserter block=”1″]

The 137 innings pitched by Cubs relievers were the fewest in baseball entering the weekend series against Arizona. So, we’re dissecting the smallest sample of an already small sample size. Even then, the bullpen has polarizing rankings in some important categories. Ranking seventh in strikeout rate is a sign of a healthy bullpen because missing bats is one way to limit late-game offense and randomness. Hector Rondon (42.9 K%) and Pedro Strop (35.9 K%) have been the best strikeout artists.

Yet, the pen plays with fire by issuing late-inning free passes. The walk rate is tied for the sixth highest among bullpens. For what it’s worth: take out the six issued in a four-day stretch to Nationals star Bryce Harper (basically intentionally as part of a strategy) and it moves the Cubs to a 9.5 BB%, out of the bottom 10 and closer to league average.

When runners reach, the Cubs’ 77 percent strand rate is above average and safely in the top-10. To go along with a high strikeout rate, Rondon also has been fortunate to have a 93.8 LOB% that ranked as the 10th best in baseball. The Cubs are no stranger to this good fortune.[adinserter block=”2″]

The good news is that the bullpen hasn’t been bludgeoned by BABIP, as the .242 mark is the second lowest in baseball. A unique combination of pitchers inducing a top-10 ranking in soft-hit percentage and ground ball rate, plus steady defense probably helps suppress the BABIP monster. And while there will likely be some regression to the mean there, minimizing hard contact likely means the decline won’t be too steep.

Trevor Cahill (28.4%) is the only Cub reliever to rank in the top 30 in soft-hit rate, but Wood (46.4%) and Justin Grimm (44%) rank in the top 10 in hard-hit rate.

Fastballs have hurt Cubs relievers with a weighted pitch value ranks near the bottom on a per 100-pitch basis, according to FanGraphs. Specifically, Cahill (-5.2) and Grimm (-3.2) have been hurt most here.

However, they have found varying success using their other pitches. Strop’s 4.0 runs saved on his slider ranks seventh among relievers, Wood’s 2.1 runs on his cutter ranks fifth, Grimm’s 5.6 runs on his curveball ranks second, and Cahill (4.1 runs, 2nd) and Adam Warren (3.3 runs, 5th) both rank in the top five in changeups.

For what it’s worth, the best pitchers are getting the bulk of the high leverage spots. Strop and Rondon have combined to face 44 of the 83 batters in these situations. That duo has combined to strike out 34.1 percent of those batters. Strop has yielded a high soft-hit rate, while Rondon has posted a 54.5 percent ground ball rate – which is usually good, but might explain an eye-popping .364 BABIP.

[adinserter block=”3″]Perhaps Grimm is ready to take that next step if he continues to excel in medium-leverage situations, especially if his 31.3 K% plays up. Meanwhile, Warren could stand to gain some trust here, but walking five of 35 batters (14.3 BB%) is too high for late-game situations.

Cahill could find himself earning more trust along the way if he keeps up a 63.6 GB% to go along with a strand rate that was above 90 percent entering the weekend.