Is slugging the way forward?

The Houston Astros seemingly have a new preference when it comes to finding new players, and building their lineup: players who slug. Power has been the foundation of their new lineup, and has underpinned the majority of their new acquisitions. Does he get on base? That's nice, but we need players who slug.

This season, the Astros were an offensive juggernaut: they scored the sixth most runs in all of baseball (the fifth most in the American League). Yet, despite this, they ranked in the bottom half in team on base percentage, and had the ninth lowest batting average of any team. Getting on base once underpinned the moneyball philosophy, but times seem to have moved forward. It's no coincidence that the Astros did, however, rank second in all of baseball in slugging percentage, and second in isolated slugging percentage.

Therefore, I decided to investigate the relationship between team runs scored with slugging percentage, and wRC+ -- I selected wRC+ as it's vastly regarded as the best, and most accurate measure of a player's offensive abilities. The results are certainly interesting, and seem to prove the above hypothesis: slugging is the way forward.

The relationship between a team's wRC+ and their runs scored isn't overly strong, with an R squared of 0.43. A statistic that's widely viewed as the best measure of a player's offense, bared a relationship that wasn't overly strong with the number of runs a given team scored. So, essentially, teams with talented offensive players, didn't necessarily score more runs. On the other hand...

The relationship between a team's slugging percentage and their runs scored is pretty strong, with an R squared of 0.76. Perhaps more interesting, the huge outlier: the Blue Jays. They slugged at a rate that was significantly higher than any other team, and as a result scored significantly more runs than any other team. I've used only data from this season as the run environment changes every year, and, perhaps, the Astros are tailoring their roster to the run environment. Fangraphs' Guts! page can explain a little more about the run environment, coming into the season.

The difference between the run environment in 2008 and the run environment coming into the season doesn't seem overly great, however, over the course of the season it pays serious dividends. If the Astros hit the same amount of home runs in 2008 and in 2014, they'd be 25 runs better off now. On the other hand, if the Cubs walked at the same rate as they did this year in 2008, they would be 10.8 runs worse off this year. So, the run environment stipulated that the Astros should adopt a preference to slugging, and indeed they did.

On the season, the Astros had only three players with slugging percentages below .400, and two of them (Carlos Gomez and Jake Marisnick) stole plenty of bases, while all three (Gomez, Marsnick and Jason Castro) played stellar defense. The rest of the roster slugged, and then slugged some more. The other thirteen players all had a slugging percentage that was above .400 and six of those players had an ISO that was north of .200. Power played serious dividends for the Astros.

A narrative I've been returning to lots recently, is the narrative of the disappointment of Evan Gattis and Chris Carter. They had a combined wRC+ of 100, which is bang on league average (league average for all hitters, the average for a first baseman and a DH is around 110), and a combined WAR of 0.3. We had high hopes for the two sluggers, but they, on the face of it, struggled big time.

However, the Astros continued to place their trust in the two, and by the end of the season, they had combined for 1064 plate appearances on a playoff calibre team. At the time, it was certainly interesting, and somewhat frustrating. However, with hindsight, it may have been insightful. We've seen, already, the importance of slugging, and if there is one thing Gattis and Carter can do, it's slug.

Slugging is far from a market inefficiency, teams are fully aware of the value of a player who can slug. However, often, players are overlooked if they struggle to get on base enough, or hit for a low average. Yet, the results of the 2015 Houston Astros may just prove that things are changing. Somebody like Evan Gattis, who as a DH, produced pretty paltry numbers (as discussed above) may be overlooked on the heels of his 2015 campaign, when in reality, he may have been a crucial offensive player for the Astros, solely because of his power.

This offseason will be incredibly interesting, as we wait and see if the Astros continue on with the same trend: acquiring and developing powerful players who slug, in order to build upon their already powerful lineup. In conclusion, slugging is hardly the sole answer to winning baseball games, but, it does seem that the more you slug, the more runs you'll score in today's run environment. Is slugging the way forward? I think so, anyway.