Ben True and Hassan Mead were close at 2014 Payton Jordan with 13:02s, but neither have touched those times since.
Also to consider, Ryan Hill, Evan Jager, Eric Jenkins and Will Geoghegan.
Evan Jager is a temping pick based on the incredible fitness he reached last summer.
My pick is Eric Jenkins in 2017. Next year is an Olympic year so people won't be chasing times as much and 2017 will give Jenkins an additional year to develop.