20704271-mmmain.jpg

The Red Bulls are sending midfielder Lloyd Sam to D.C. United. (Geoff Burke | USA TODAY Sports)

New York Red Bulls midfielder Lloyd Sam has to face the harsh reality of MLS's transfer window: After spending his entire MLS career with the Red Bulls, Sam was essentially sold to D.C. United.

A league source, who requested anonymity because that person was not authorized to speak, confirmed to NJ Advance Media on Thursday that the Red Bulls traded Sam to D.C. United for an unspecified amount of allocation money.

Sam became the Red Bulls' first victim of the secondary MLS transfer window, which began on July 4. Red Bulls coach Jesse Marsch previously told reporters that the team was looking to bolster their attack through the transfer window.

"We have some different resources, so we're trying to act responsibly in this transfer window and have an open mind to a potential big addition," Marsch told reporters after Tuesday's practice.

Marsch didn't rule out adding a designated player through the transfer window. Bradley Wright-Phillips and Gonzalo Veron are the team's two Designated Players, and the club would need to pay the MLS $150,000 for a third Designated Player.

Why is this relevant? The Red Bulls traded Sam for general allocation money, and that will give he Red Bulls front office will have more cap flexibility. They can use the money to reduce an existing player's cap hit, or they could also use it reduce the cap hit of a potential signing, which might help the Red Bulls avoid using their third Designated Player spot.

Marsch has not used Sam in the starting lineup in the past two MLS games. Homegrown talent Alex Muyl has started in his place and stands the most to gain in Sam's absence.

Sam played five seasons for the Red Bulls and now he'll be playing for their bitter Eastern Conference rival, D.C. United. Sam has scored five goals in nine regular-season appearances against D.C. United, and he played all 90 minutes in the Red Bulls Eastern Conference semifinal victory over D.C. United in 2015.

Prior to joining the Red Bulls, Sam played three seasons in the English Premier league. Sam has tallied 39 goals in 317 career appearances.

The Red Bulls' next MLS game is against the Portland Timbers on Sunday at Red Bull Arena.

Daniel Falkenheim may be reached at DFalkenheim@njadvancemedia.com. Follow him on Twitter @Thefalkon. Find NJ.com on Facebook.