Tom Tango follows up on his Run Expectancy post with a primer on calculating the value of a home run. The average home run is worth 1.4 runs. He then makes a comparison between Mike Trout and J.D. Martinez (emphasis added):

Let’s compare Mike Trout to JD Martinez, since 2012. Trout hits only 36% of his HR with a runner on base, while JD hits 48% with a runner on base. This means that the average JD’s homerun has been worth more than the average Trout homerun. Those run values are 1.29 for Trout and 1.47 for JD.

While there’s no real skill to doing it, the teams do in fact benefit from it. Should we simply count every HR as being worth 1.4 runs, or, should we count them based on what actually happened? If you count based on reality, that means HR hit with bases empty count for less than HR hit with runners on base.

TangoTiger.com

This strikes me as a great example of the skills of teammates amplifying each other. Martinez tended to be surrounded by better players during this time period. Martinez came to the plate with 3762 runners on base over the last eleven years, Trout with 3295 runners. The batters in front of Trout did less to amplify his long balls. Note, however, that Trout overall drove in a higher percentage of runners than Martinez, so home runs with men on base aren’t everything.

Note also that Trout amplified Albert Pujols‘s abilities. Pujols tended to bat behind Trout during that time period, and Pujols came up with 3838 runners on base. He drove in an even higher percentage of those runners than Trout did.

Trout made the rest of the Angels better for a decade. The Angels need to add players to better amplify Trout’s abilities.