Breaking Down the Astros’ 2015 Offensive Changes

The Astros were baseball’s biggest surprise of the 2015 season. Few will dispute that. This was, however, preceded by some of the worst seasons in Houston history. They posted three consecutive 100+ loss seasons from 2011-2013 followed by a somewhat bounceback 2014 campaign, posting a 70-92 record. Although they were not quite back to the winning tradition that ‘Stros fans enjoyed during the late 1990’s and early 2000’s, young potential began to show, headed by silver slugger Jose Altuve. The combination of young talent with free agent and trade market moves led to an unexpected 86-76 season and the first playoff birth since 2005 (where they eventually got swept by the White Sox in the Fall Classic). Part of this success was due to a new-found, solid bullpen and front five led by Cy Young winner Dallas Keuchel. However, the more exciting part of their success — at least for the average fan — was the explosive offense.

Houston’s 2015 opening day lineup included four new players to the organization: Luis Valbuena, Jed Lowrie, Colby Rasmus and Evan Gattis, all of which had 15+ home run seasons in the past. These lineup changes were complemented by a new hitting coach in Dave Hudgens, who preaches that being aggressive in the zone leads to a higher OBP, harder hit balls, and more runs scored. This proved to be a highly successful match, as the Astros posted impressive power numbers. They were second in the league in ISO, SLG, and home runs (all behind the Blue Jays), according to fangraphs.com. Their team wRC+ of 105 was 4th best in the league and was the best wRC+ since back in 2000 – the first year of Minute Maid Park. The most recent yearly changes have been the most impressive numbers, however.

From 2014 to 2015, they had the biggest increase in all three aforementioned categories of any team in baseball, adding 67 home runs, .046 ISO, and .054 SLG. They also increased their Z-swing% by 3.5% to 70.2%, the highest in the league and right in line with Hudgens’ approach. Surprisingly, they did this while decreasing their K% (albeit only by 0.9%). This leads to the question of how big of an impact Hudgens had on the organization and its multitude of young power hitters.

There were 11 Astros who had double-digit home runs, all who are younger than 30 years old. Five of those players broke the 20-home-run mark (Gattis – 27, Rasmus – 25, Valbuena – 25, Chris Carter – 24, Carlos Correa – 22). This is not including 29-year-old Carlos Gomez who was acquired in the latter half of the season, who only hit 12 home runs throughout his injury-plagued 2015 season. With so much raw power and youth in the organization, an active hitting coach is crucial to develop successful hitting approaches and general consistency at the plate. Hudgens seems to have been very successful in extracting the most out of his hitters in his first year.

Many of these hitters took strides to becoming more balanced at the plate. For example, slugger George Springer who posted a miserable 33.0% K% in his 2014 rookie campaign came down to a more reasonable 24.2% in 2015 while posting an above-average ISO of .183. The biggest surprise in this is that that is his lowest strikeout rate of any full year in his baseball career, including rookie and high-A ball. Another highly noticeable change is the power numbers of All-Star second baseman Jose Altuve. Known for being more of a contact hitter, the 5’6″ Venezuelan hit 15 home runs (the first double-digit home run season for Altuve) and improved his ISO from a below-average .112 in 2014 to a career high of .146. Teammates Luis Valbuena and Colby Rasmus also posted career highs in ISO at .214 and .236, respectively.

The good news for Astros fans is that this offense appears sustainable. The BABIP numbers of these Astros hitters slightly decreased for the most part. The glaring exception is George Springer, who had a BABIP of .342 compared to his rookie year’s .294 (but with his strikeout rate decreasing 8.8% and OBP increasing by .031, only time will tell if he can continue his impressive numbers at the plate once pitchers adjust and approach him differently). The Houston front office has built an offense around around younger hitters with a lot of raw power. This is not to mention their speed, as they ranked 3rd in stolen bases last year. So although the AL West has shown to be unpredictable in recent years, the way the Astros have built their team may very well provide some sustainability for them moving forward.

Side note – don’t expect the Astros to remain quiet in the off-season just because of their youth-heavy core. They have already begun shopping Jake Marisnick after retaining Colby Rasmus with a 15.8MM qualifying offer.