IIRC, he wore out his welcome in MLS. DC tired of him and shifted him to some nondescript team, where it really didn't work out for him. It was more his youth-level performances that have salivated the mouths of European clubs.
Yeah, he really had no choice but to leave. Had a fallout with the manager at DC, traded off to Real Salt Lake, who were probably the worst team in the league at that point. He played a season or two there as their best player, but it was going nowhere. Staying in the MLS longer would have definitely helped, just didn't work out that way.