Understanding John Axford's Scoreless Streak

2013 has been a tale of two seasons for Milwaukee Brewers closer John Axford

Beginning the season with an Opening Day blown save, Axford's headaches continued in his next three outings (2.1 IP) when he yielded a total of eight earned runs on eight hits (including three home runs) and two walks with a fly-ball to ground-ball ratio of 13-to-1. After being demoted from his closer role, his next month's worth of appearances were primarily spent in innings other than the ninth, and he performed well, lowering his season peak ERA of 24.30 on April 9 down to 9.20 as of May 14.

And May 14 marks the last time Axford has let a run cross home plate

Since then: 

• He's tossed 17.1 innings of scoreless baseball
• Struck out 18, walking seven
• Held hitters to a slash line of .180/.275/.213 with just 11 hits allowed. 

His turnaround has had a ripple effect on Milwaukee's bullpen, too, posting an ERA of 2.45 as a staff, which ranks second-best in baseball since that date.

Axford's success can be traced largely to his success against lefties

	Zone%	In-play%	Miss%	Chase%	Well Hit Avg (BAA)
Apr. 1-May 14	49.3%	44.0%	26.0%	16.2%	.300 (.400)
May 15- June 22	41.7%	30.9%	34.5%	25.9%	.115 (.154)

• The most prominent deviation against left-handed opponents comes on the in-play rate; nearly a 14-point difference in the amount of pitches hit in play is enough to say that either a) Axford's approach has changed and his command has improved or b) it is simply a matter of coincidence.
• When you are looking at the world through an analytic eye, you don't buy into "coincidences." So, despite the fact that Axford is throwing less pitches in the zone, evidenced by his 41.7% zone rate, lefties are swinging more frequently at pitches that are not in the zone (25.9% chase rate).
• Consequently, lefites are having a more difficult time making hard contact on his offerings, as his signficantly decreased .155 WHAV indicates.

Axford's approach within the strike zone.

These maps compare pitch frequency

• Early in the season, Axford was much too over the plate with his offerings aganst lefties, pitching into a portion of the zone where left-handed batters produce a large portion of their extra-base hits. 
• While his command could certainly be better during his scoreless streak, he has made it a point to stray away from the lower portions of the strike zone with his offerings, focusing instead on the up-and-outside portion of the zone to which left-handers traditionally are less apt to generate extra-base hits.
• Axford has also focussed more on 'painting' the edges of the zone more frequently than he did prior to his late success, especially down and inside. Since Axford is more cautious within the zone, lefties are finding difficulty in putting quality contact on the ball.

April -May 14 contact rate and hit charts

During Axford's scoreless streak

• Early in the season, Axford pitched more frequently to left-hander's strengths within the zone resulting in solid contact and power

• During his scoreless streak, lefties have primarily made contact on pitches that are in on their hands, and that has resulted in weaker contact and subsequent lazy fly-ball outs.

With the July 31 non-waiver trade deadline approaching, it's tough to say whether Axford's scoreless streak has made him a legitimate asset in a package deal. If it continues well in July, general manager Doug Melvin may have no other choice but to move him to a buyer in need of late-inning help out of the bullpen. But, for now at least, the Brewers may want to ride Axford's scoreless streak for as long as possible -- there hasn't been much worth cheering for this season.