Bruce Arena admits his players were suffering fatigue when they lost to Carolina RailHawks in the US Open Cup on Tuesday.

The reigning MLS champions crashed out of the cup competition 2-1 to the NASL outfit with Arena trying to shuffle his defence late in the game.

The Galaxy boss left out three key defenders in AJ DeLaGarza, Sean Franklin and Todd Dunivant, using the returning Leonardo for a full 90 minutes, and admits it was a tough task for his defensive unit.

"We were resting our other three backs who had played a lot of games and we've had a lot of games in a short period of time, so we had to shuffle as best we could the remaining defenders," Arena said.

Arena added that he felt some of his players were feeling the strain when his side were up 1-0 in the 75th minute, forcing him to make all three substitutions.

"It's a point in the game where we were a little fatigued," Arena added. "We'd used all three of our changes at that point.

"We had some unfortunate injuries. They were more aggressive obviously in the last 30 minutes."

It just continues to get worse for the Galaxy, who are now out of the cup running, after falling to the bottom of the Western Conference with just three wins from 13 MLS outings.

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