FanPost

Why I wouldn't worry TOO much about Stephen Souza's batting average

Bob DeChiara-USA TODAY Sports

I have a bad habit of burying the lead, so this time I won't :

My Projection for Souza in 2018 for the Diamondbacks is .257/.358/.465 .823 OPS

I have been reading on twitter and in various threads and sites concern about the fact that Stephen Souza had a .239 batting average last year and has hit .236 for his career. I'm here to tell you that it's not as bad as you think, and in fact his batting avg is not all that far below average when you take context into account. Don't get me wrong, Souza is never going to win a batting title, and is unlikely to ever approach .300 batting avg. Not with a K% around 30% even in his career year. But the CONTEXT of where he has been playing , Tropicana Field, and it's impacts, really needs a good look to understand this player.

Everyone who reads here has seen Park Factors and Park adjusted metrics such as OPS+ or wRC+ etc. referenced frequently, on a daily basis. The premise of these metrics, scaling everything to 100 with over and under 100 representing how much over/under average is simple enough. But I think perhaps what is lost is an actual visual of what that means when looking at the numbers we see first for hitters......the triple slash of B.A./OBP/SLG. and OPS

Baseball reference provides us with an alternate view of how different environments affect the hitting numbers.

On each teams page, you can find under the batting statistic drop down an area that says "detailed Stats", and within that page, you can scroll down to "Team Advanced Batting". In that section you will find "lgBA" column. Hovering your mouse over that column heading, you see the words:

League Batting Average: The batting average a league average (non pitcher) would have in the same park(s)

The same columns exist for OBP , SLG, and OPS.

Here are the links for the DBacks 2017 and also Rays 2017

And here, quite simply is how they compare. STOP RIGHT HERE AND ABSORB THIS LITTLE TABLE

lgBA lgOBP lgSLG lgOPS
Chase .272 .346 .456 .802
Tropicana .249 .316 .418 .735


Now that is a massive difference, is it not? Go back and look again ! The park impact is 23 points of batting average ? Well it was last year. 3o points for OBP. 38 points for slugging. 67 points of OPS in total.

In 2017 Stephen Souza hit .239/.351/.459 Playing his home games in a ballpark that suppresses these batting numbers tremendously compared to Chase field. He was just 10 BA points below average for his ballpark. What would these numbers look like converted to a Chase Field Environment ? Well we can get there by looking at the percentage of the average line in Tropicana that Souza put up, and converting that to Chase's average line:

lgBA lgOBP lgSLG lgOPS
Chase .272 .346 .456 .802
Tropicana .249 .316 .418 .735
Souza .239 .351 .459 .810
Souza % vs Trop avg .960 1.111 1.098
Chase Adjusted Souza line .261 .384 .501 .885

WOW !. Quite a difference, huh ? His batting avg went up 22 points, his obp 33 points, slugging 42 points, and his OPS 75 points in total. This is a massive adjustment. But thats how extremely different the parks played in 2017

Back to OPS+

So lets look at this in reverse now for a few sets of players. By OPS+ they were ranked roughly the same, but look at the large difference in OPS . This is why we use the park adjust metrics. The work is already done for us, and our view is not obfuscated by the raw numbers before adjustments. Most people would not look at these batting lines and think they were the same value. But they were.

Player OPS+ OPS BA OBP SLG
Evan Longoria 100 .737 .261 .313 .424
AJ Pollock 99 .801 .266 .330 .471
Brad Miller 84 .664 .201 .327 .337
Daniel Descalso 82 .727 .233 .332 .395
Kevin Kiermaier 114 .788 .276 .338 .450
Chris Iannetta 114 .865 .254 .354 .511


Now back to Souza and How I arrived at the projection for him leading off this post:

Keep in mind Souza had a career year last year. It would be great if he can repeat that, or even build on that and continue to get better. But if you are doing projections, you can't allow your fandom or optimism to impact objective analysis. But we CAN and SHOULD adjust his numbers for his new environment.

If you go to Souza's fan graphs page you can now see both ZIPS and STEAMER projections, and an averaged "Depth Chart" projection. Ignore the counting stats, as playing time is too variable. You can see he is projected to a triple slash of .239/.331/.434 .775 OPS. But that is in Tropicana field. So I am converting that to Chase.

But Chase and Tropicana will not play exactly as it did in 2017, and the league wide run environments won't be exactly the same either. Runs per game league wide go up and down all the time. Will the ball still be juiced ? (Yes it was). What about the Humidor and it's effect ? We just can't know the future trend. But we can at least weight the recent past and come up with a reasonable guess. (Once we have a year with the Humidor in place, this could change a lot of course)

Chase BA OBP SLG OPS
2017 .272 .346 .456 .802
2016 .268 .339 .438 .777
2015 .266 .331 .419 .750
straight avg .269 .339 .438 .776
weighted avg .269 .341 .443 .784

Tropicana BA OBP SLG OPS
2017 .249 .316 .418 .734
2016 .252 .315 .414 .729
2015 .251 .313 .406 .719
straight avg .251 .315 .413 .727
weighted avg .250 .315 .414 .729

So looking at those two charts, you can see I came up with both straight average and weighted average, in this case I used 3.2.1 weighting. (2017 * 50%, 2016 * 33%, 2015 * 17%). From there you calculate a simple conversion rate and apply it to Souza's Tropican Projection

BA OBP SLG OPS
Conversion rate 1.077 1.083 1.070
Souza FG Proj .239 .331 .434 .765
Revised Projection .257 .358 .465 .823

So that is how I figured his projection for 2018. If the Humidor has a large impact, the raw slash might not look so good of course. In fact it may revert back to the Tropicana like projection for all I know. But the "relative value" will still be the same....we hope.

Two last points on Mr. Souza that I think is important:

Plate Discipline:

Despite his strikeouts, he actually had a major improvement in a key area of his Plate Discipline . His percentage of pitches outside the strike zone (O-Swing) swung at dropped from 30.6% in 2016 to 24.4% in 2017. This was the key driver to his vastly improved Walk %. While it's expected that both numbers would regress some, if he maintains that approach he should continue to see double digit walk %, even if not quite as high as last years 13%. He's projected to have 11% walk rate for 2018.

Defense:

A full season of defense is usually at least 1000 Innings,. It takes 3 years of innings for defense numbers to give us the clearest picture possible on a player's defense. In Souza's case, he's got 3 years and a cup of of coffee in the majors, and 3,104 defensive innings. I wouldn't parse the year by year too much in trying to figure out his fielding talent. His career numbers are your best indicator at this point:

rDRS career Per 650 PA
5 1
UZR career Per 150G
7.2 3.9

So that looks like at least average to slightly above average, which is clearly going to be an upgrade over Tomas or JD Martinez most likely.

One thing that is notable if you look at his UZR numbers in detail: He's + 1.3 for Arm, and + 7.6 for Range, but -1.7 for Errors. So he will probably be a net positive, but he's prone to make some errors out there, and playing in new parks might not help him cut down on the errors.

SUMMARY:

He's probably going to strike out 150-180 times depending on how much he plays, and he'll make a few extra goofs in the outfield. But he's going to field well enough, throw well enough, and hit with enough power and get on base enough to be a positive contributer. My Good Friend Fangdango ;) expressed something that rings true:

He’s going to make some great plays and some ugly ones. He’s going to have some great at bats and lots of ugly ones. I think he’s the kind of player that will give us something to talk about almost every day, good and bad. Hopefully a lot more good than bad.

I do believe the overall contribution will be positive. He won't be an all star, and he will generate plenty of debate between people who view and assess talent somewhat differently. He didn't come cheaply. And the team is trying to win now. I'm hopeful he is a positive addition that helps the team achieve greater heights in 2018