"Surgery tomorrow -__-wish I was out there with the homies tomorrow vs el salvador. miss the squad already."
Agudelo was diagnosed with a meniscus tear in his left knee after injuring it during the United States' win over Cuba in the opening game of their Olympic qualifying campaign.
The striker returned to New York on Sunday to consult with Red Bulls medical staff about how to proceed with a course of treatment.
The decision to undergo surgery means Agudelo will miss three to six weeks. The player was optimistic, pointing to the low end of that range, saying, "I'm pretty young so I heal up quick."
By contrast, New York head coach Hans Backe estimated Agudelo would be out a "minimum of six weeks."
Reaction from Agudelo's U.S. teammates came in quickly.
Fellow U-23 forward Terrence Boyd:
U.S. goalkeeper Nick Rimando:
U.S. striker Jozy Altidore:
Agudelo's injury leaves two teams in the lurch. The 19-year-old's knee couples with Luke Rodgers' ongoing problems obtaining a visa to leave Backe's Red Bulls with only two real forward options (Thierry Henry and Kenny Cooper).
Meanwhile, the United States U-23s face a must-win match against El Salvador on Monday after losing their first game without Agudelo to Canada on Saturday.