Watch Now: Highlights: Houston Dash vs. Washington Spirit (1:03)

The Washington Spirit announced Monday that midfielder and team captain Andi Sullivan will miss the remainder of NWSL Challenge Cup after suffering a torn meniscus. The injury occurred during Washington's final preliminary round match against the Houston Dash on Sunday as the midfielder pulled up as she was about to make a play on the ball. 

Sullivan immediately went down on the pitch in pain as she recognized something was not right in her knee.

"I'm obviously disappointed to not be out there playing, but I'm excited to watch the rest of the tournament and I'm hoping to see my team win it all in the end. I'm hopeful that I can continue to build off of the performances I had in the Challenge Cup after I complete rehab in a few months, and I'm confident that I will come back from this injury stronger, Sullivan said in a release. 

"I'm grateful to everyone who has reached out to me, asked me how I'm doing and sent good vibes my way. It means a lot, and I will carry those with me throughout my recovery."

Sullivan is expected to leave the NWSL Village and return to Washington D.C. for arthroscopic knee surgery to repair the cartilage on Thursday. Sullivan is expected to miss three to six months of action as she recovers. The 24-year-old will begin rehab in Sacramento post-surgery.

Sullivan was part of the USWNT's roster for the SheBelievesCup earlier this year and will try to land a spot on the national team's squad for next year's Olympics after her rehab.

The injury come as huge loss for Washington Spirit, who have been on a strong run during the Challenge Cup. That play was in large part due to Sullivan's impact on the pitch. The team currently sits in second place on the tournament standings.