Terrence Boyd has told ESPN FC it will be tough to force his way back into the United States national team after Darmstadt were relegated from the Bundesliga.
U.S. forward Boyd made his Bundesliga debut after leaving RB Leipzig for Darmstadt in January after a long spell on the sidelines with cruciate ligament injuries.
He played in seven matches, scoring against his former club Borussia Dortmund, but was then ruled out with an ankle injury.
Having made his U.S. debut under head coach Jurgen Klinsmann in 2012, Boyd also made a cameo appearance during the coach's final months in charge in 2016.
And he said he knew it would be difficult to put himself back into international contention, saying current coach Bruce Arena "has my number, but it won't get any easier in the second tier."
He added: "Bruce Arena contacted me a while ago, but to be honest I need to do my work and also be a key player for my team. I haven't been that for a number of reasons."
Boyd is under contract at Darmstadt until 2018, and said: "I need to show myself, although I am aware it won't get any easier."