You probably have heard of Three True Outcome (TTO) players. TTO refers to the three true outcomes of an at bat which do not require any action by fielders: strike out, home run, or walk. Hitters who have 45% - 50% or more of their plate appearances end in one of these outcomes are sometimes called TTO hitters. Two of the three outcomes are very good things, and one isn't. The stereotypical profile for a TTO hitter is relatively low batting average, high OBP relative to batting average, and high HR rate.
Why is this subject related to sabermetrics? First, the origin of the "TTO Hitter" has been attributed to Baseball Prospectus which originally coined the term as a tribute to Rob Deer. And B-Pro is one of the early promoters of sabermetrics on the internet. By the way, you have to laugh at this 2000 B-Pro article on TTO hitters. (A young minor league hitter by the name of Russell Branyan is crowned the prophet of TTO hitters in the article.)
Second, sabermetrics brought greater attention to the importance of HRs and walks in scoring runs, reflected in stats ranging from OPS to wOBA and Runs Created. It's fair to say that sabermetrics placed greater emphasis on OBP and SLG than "productive outs," which had become a holy grail of baseball managers in 1960's and 1970's. This change in emphasis, in turn, leads to the realization that the two positive outcomes of TTO can far outweigh the negative outcome (strike out).
Third, TTO hitters are frequently undervalued by traditional baseball organizations, because of the aversion to high strike out rates. Thus, a sabermetric organization might exploit a market inefficiency by picking up TTO hitters at a low price. For example, the Oakland A's picked up former top prospect Jack Cust, languishing on the Padres' AAA roster as a so-called 4A player, and turned him loose on the American League in 2007 - 2010. Cust is one of the highest TTO percentage players in baseball history, and he routinely gave the A's wOBA performance in the .370 - .400 range.
One of the fine people at Baseball Think Factory posted a ranking of the highest TTO percentage seasons by sluggers in baseball here. Cust's 2007 season stands atop the list at 58%, but Adam Dunn's current season is on pace to exceed Cust's TTO%. Clearly, though, some great hitters are on this list: Barry Bonds, Jim Thome, Ryan Howard, Jack Clark, Mark Maguire.
And this brings us to Justin Maxwell, whom was acquired by the Astros off waivers early this season. We know that Maxwell hits prodigious, even majestic, HRs.--- something which we associate with a lot of TTO hitters, like Russell Branyan, Adam Dunn, and Mark Maguire. I know it's not even midway through the season and we can't predict Maxwell's future performance. But so far, Maxwell's TTO percentage is 47%, easily the highest among Astros' hitters, and easily within the range of well known TTO sluggers. Chris Snyder and Brett Wallace are the Astros' hitters with the closest TTO%, (low 40's). Maxwell's .237 batting average is accompanied by a more respectable .337 wOBA.
One difference between Maxwell and many of the classic TTO sluggers is that he can play good defense at a premium outfield position. This may give Maxwell more staying power in the major leagues than the typical 4A power hitter.
But swift athletic center fielders can be TTO hitters. Bobby Bonds---Barry Bonds' father--was a TTO hitter in the context of his era, with TTO% frequently exceeding 40%, which was quite unusual in the 1970's. Bonds is often considered the prototype of the modern 30-30 slugger.
One of the trends in baseball is the increase in TTO%. So far this season, the ML average TTO% is 30%, a slight increase over 29% in 2011. As an illustration of increase in TTO% , the ML average TTO% in 1955 was 23%. One of the reasons for this trend is the tendency of MLB players and clubs to tolerate more strike outs in return for more home runs. Also, pitchers throw harder in today's game, with a comcomitant increase in strike outs. Although it is common for fans and writers to decry the aesthetic impact of higher strike out rates among hitters, the higher K rates often are associated with higher rates of both power and walks among hitters, which generally leads to more run scoring.
I got off track a little bit. So, back to Justin Maxwell. If Maxwell can maintain his current power trend, we probably will see more playing time for him--perhaps a formal platoon in CF, maybe even more playing time than a platoon. If the Astros are lucky, Jeff Luhnow may have picked up an undervalued hitter, much like Billy Bean's acquisition of the TTO King, Jack Cust.