One often hear how a certain player is a slow starter or maybe tires at the end of a season. Mark Trumbo is a player you often hear about fitting within the latter group. You may see people throw out his current wOBA splits of .388 and .210 in the halves of this current season. Those who dig a little more will note how his career line is .342 and .325, respectively. The numbers paint an interesting picture that appears to line up with conventional wisdom. That said, I think there is little basis for that conclusion.
Below is a table for Trumbo half seasons for every full season of his career to date:
What immediately becomes clear is that this is not a conclusive rule on Trumbo. His 2014 and 2015 seasons show nothing of a player who tires out down the stretch. In fact, the difference in his career line seems to come from rather extraordinary 2012 and 2016 first halves. If you do a simple paired t-test, you find no significant differences between those sets of numbers.
Ultimately, we should expect Trumbo to move forward and maintain a wOBA of about .330.