Brayan Pena Should Not be an Everyday Starter

It's the end of May and just past the ¼ mark of the season, which means there's enough playing time for people to stop using the "it's early" and "small sample size" excuses. One such instance is Alex Avila, who has gotten off to a horrible start, hitting only .179/.256/.304 with a 51 wRC+ in 125 PA. In the meantime, Brayan Pena has much better numbers, hitting .275/.296/.412 with an 88 wRC+, but in only 55 PA. Tiger fans are fed up and want a change.

@eyeontigers @bossofrenfield Right now, Pena is far superior to Avila.Avila has been a complete turd. Pena needs more playing time right now
— Jonathan Knerr (@JonathanKnerr) May 21, 2013

As well as posts from Detroit Tigers.com message board and Motown Sports message board.

Looking deeper in the numbers, it doesn't appear that Pena would be much of an upgrade.

First of all, historical stats say that Avila is a better hitter:

Brayan Pena:

Year	PA	AVG	OBP	SLG	BB%	K%	wOBA	wRC+
2010	174	0.253	0.306	0.335	6.9%	15.5%	0.288	75
2011	240	0.248	0.288	0.338	5.0%	10.0%	0.277	70
2012	226	0.236	0.262	0.321	4.0%	10.6%	0.254	55
2010-2012	640	0.245	0.284	0.331	5.2%	11.7%	0.272	66

Alex Avila:

Year	PA	AVG	OBP	SLG	BB%	K%	wOBA	wRC+
2010	333	0.228	0.316	0.340	10.8%	21.3%	0.299	81
2011	551	0.295	0.389	0.506	13.2%	23.8%	0.384	141
2012	434	0.243	0.352	0.384	14.1%	24.0%	0.327	104
2010-2012	1318	0.260	0.358	0.423	12.9%	23.2%	0.343	114

Even if Avila's 2011 season gets heavily discounted because of a fluky career year, his 81 wRC+ in 2010 is still better than any of the last 3 years by Pena. The only year that Pena has done better than an 81 wRC+ and had significant playing time was in 2009, when he had a 94 wRC+. The same principle of fluky career year could also be applied to that year too since he hasn't come close to matching that until the 13 games he's played so far this year.

So maybe Pena is doing something different. Maybe he's changed his approach to become a more successful hitter?

Year	BABIP	LD%	GB%	FB%
2010	0.295	16.3%	45.0%	38.8%
2011	0.261	22.9%	44.3%	32.8%
2012	0.253	24.6%	48.2%	27.2%
2013	0.279	11.1%	57.8%	31.1%
Career	0.266	20.9%	48.8%	30.3%

There's definitely a huge increase of ground balls, and a decrease in line drives. Pena has 14 hits and 7 of them have been hit on the ground (including 3 infield hits). That's 50% of his hits coming from ground balls compared to 34% in both 2012 and his career. Pena isn't the fleetest of foot, so to have him have continued success by hitting ground balls instead of line drives isn't very likely. This is likely random variance from only playing in 13 games.

Here are his plate discipline numbers:

Year	O-Swing%	Z-Swing%	Swing%	O-Contact%	Z-Contact%	Contact%	Zone%
2010	31.4%	64.5%	48.5%	65.6%	90.5%	82.7%	51.7%
2011	28.7%	61.0%	45.1%	79.4%	93.9%	89.4%	50.6%
2012	31.9%	60.4%	46.5%	76.7%	94.5%	88.5%	51.1%
2013	29.5%	63.0%	45.9%	67.7%	95.2%	86.2%	48.8%
Career	30.5%	61.2%	45.8%	76.7%	93.5%	87.9%	49.8%

There isn't much difference in his 2013 numbers than his recent seasons or his career totals. The stat with the most difference is his O-Contact rate is lower, which means when he swings at pitches out of the strike zone, he's missing more often. That is the opposite of an improvement.

What about Avila? Is he doing something different to cause less success?

Year	BABIP	LD%	GB%	FB%
2010	0.278	21.5%	43.5%	35.0%
2011	0.366	21.7%	37.8%	40.5%
2012	0.313	23.8%	46.4%	29.8%
2013	0.219	19.7%	50.0%	30.3%
Career	0.316	21.7%	42.8%	35.5%

Avila's BABIP is down almost 100 points from last year and his career. His batted ball data doesn't have a dramatic change from his previous seasons and his career. Therefore, it's reasonable to conclude that Avila is either suffering from BABIP bad luck or an injury is causing it.

Avila's plate disciple numbers:

Year	O-Swing%	Z-Swing%	Swing%	O-Contact%	Z-Contact%	Contact%	Zone%
2010	23.4%	64.3%	44.2%	52.3%	86.8%	77.8%	50.7%
2011	24.7%	60.2%	43.0%	49.0%	86.1%	75.8%	51.5%
2012	20.9%	58.7%	39.3%	51.6%	82.1%	73.8%	48.8%
2013	20.3%	62.8%	42.0%	46.3%	79.3%	71.5%	51.0%
Career	22.6%	61.1%	42.1%	49.9%	84.7%	75.5%	50.5%

Avila's main problem is his Contact%, both in the strike zone and out of the zone. He's swinging and missing more often than he ever did, which definitely explains the increase in strikeouts (28.8% in 2013) and decrease in walks (9.6% in 2013). It's hard to imagine a 26 year old suddenly become a weaker hitter than he was a year ago, so I'm leaning towards the injury theory.

Finally, there's ZIPS rest of the season stats. While these stats don't show exactly what will happen in the future, they do show who is likely to be better for the rest of the season.

Player	PA	AVG	OBP	SLG	BB%	K%	wOBA	wRC+
Brayan Pena	164	0.260	0.293	0.369	4.3%	11.8%	0.290	77
Alex Avila	351	0.236	0.334	0.390	12.6%	25.3%	0.320	97

Alex Avila may need to be replaced (or DL'd), but the answer isn't Brayan Pena.