One of the reasons that Jedd Gyorko is a member of the Cardinals is the second-half drop-off of Kolten Wong. Wong's fantastic first-half of 2015 was derailed by a second half that saw him hit .238 with zero home runs post-July.
In his best cumulative professional season, Kolten Wong again showed the inconsistency that has frustrated fantasy owners since he reached the majors. After a mediocre 2014, he got off to a great start in 2015, hitting .280 with nine home runs and 44 RBI through the first half. But then he ran face-first into a wall, which Fangraphs' Steven Shumansky thinks was directly related to fatigue. Considering that Wong played in 37 more games in 2015 than 2014, as well as saw his GB% increase by 5% between halves, the numbers play into that theory. If that is the case, there is good chance that with better conditioning, Wong's best season could be right around the corner.
Source: Fangraphs