Send the U21 manager a PM to try to get on their tracking list, but unless he's been getting really, really good one position training all season I can't imagine he's up to par for the US u21 team with such a low salary and DMI (although the DMI is low in part due to the terrible game shape - but game shape management is another issue that could keep him off the team even if his skills are up to par).
The lowest salary on the team is $19k and the lowest DMI is 129k - your guy is nowhere near either of those markers. Still - send the coach a PM and see what you can do to try to get him up to par.