If given only a few metrics to look over, many would suspect that the Yankees pitching staff is absolutely killing it in 2016. The group ranks second in the Majors in BB/9 (2.50), second in GB% (50.4%), third in K/9 (9.10), third in xFIP (3.46), and 9th in fWAR (4.5). Hell, they even lead the Majors in SIERA (which is essentially a Super xFIP that factors in batted ball data).
Despite all of this, the Yankees sit 20th in baseball with a 4.44 ERA. How did we get here?
To be frank, there is no clear-cut answer ... which may make all of this meaningless. The usual caveats of 'small sample size' and 'it's May 19' apply. And it is also difficult to capture the nebulous command issues that have plagued Michael Pineda and Luis Severino. But when has that ever stopped us before?
As of this writing, the Yankees have allowed a league-worst 17.0% HR/FB. Thanks to their groundball tendencies, however, they are a bit better insofar as actual home runs are concerned, checking in at 26th in HR/9 (1.37). That suggests that when opposing hitters are able to loft the ball, they are doing so with authority - but that's not entirely true, as the Yankees are 10th in the Majors in hard-hit percentage. Is it luck, then? Or is it a matter of playing in New Yankee Stadium? For better or worse, it may actually be a combination of the two.
The Yankees have played 39 games thus far - 22 at home, and 17 on the road. Thirty-six of the fifty-two home runs that they've allowed have come at NYS. Interestingly this may be somewhat by design. Yankees pitchers have issued 3.04 BB/9 on the road, but only 2.12 BB/9. The discrepancy in K/9 is similarly substantial - 9.41 at home, and 8.66 elsewhere. Could this be a conscious approach, where the pitching staff is attempting to limit base-runners in their hitter-friendly home park by pounding the strike zone? Or is it just white noise created by splitting hairs in an already small sample size?
This was not the case in 2015, where the numbers were similar across the board. In 2013 and 2014, however, there was a similar gap between walk and strikeout rates.
It is also worth noting that the Yankees strong control numbers have been somewhat mitigated by their hittability. They currently sit 19th in BAA (.258) and 25th in BABIP (.311), which has them allowing a roughly league-average amount of base-runners (their 1.29 WHIP is 0.03 above-average). Allowing an average amount of base-runners and a hell of a lot of home runs is a quick way to give up too many runs. Moreover, hits advance base-runners far better than walks (setting up better scoring opportunities).
So what does it all mean?
At face value, there is a bit of hope here. The defense should improve (it improved markedly as last season went on), which should help limit some of the base hits that are dropping in. And, if xFIP and SIERA are to be trusted, some of the balls that are flying over the wall should die out somewhere in front of the wall. This is the first time that the Yankees pitching staff has been below-average (in terms of run prevention) with Larry Rothschild at the helm, and he has earned our trust.
To be fair, though, the staff does need to step-up. Nathan Eovaldi showed what he can do when his command is on last night (and was quite good as the season progressed in 2015), and Messrs Michael Pineda and Luis Severino are not this bad. A bit of improvement on an individual level should pay dividends on the whole.
Despite my general pessimism, I do think that some positive regression will happen. And I would hazard that the pitching staff as a whole will be considerably closer to average once more at season's end.