Freestyle snowmobile rider Caleb Moore remains in intensive care Sunday with a "secondary complication involving his brain" and bleeding around his heart after a serious crash at ESPN’s Winter X Games in Aspen,CO.

Moore, 25, fell short of a complete rotation while attempting a backflip in the competition and was thrown from his sled. Weighing in a 450 pounds, Moore’s sled hit the rider upon landing, knocking him unconscious for a brief moment. The X Games athlete walked away from the crash, but was taken to the Aspen Valley Hospital soon after.

According to ESPN, Moore developed bleeding around his heart while at the hospital and was then flown to Grand Junction for surgery Friday.

On Sunday, a family spokeswoman said Moore's injuries include "a secondary complication involving his brain."

"Caleb continues to be monitored in ICU," Chelsea Lawson told The Denver Post. "His cardiac injury has led to secondary complication involving his brain. The Moore family thanks all of Caleb's fans and friends for their support and for respecting their privacy."

In related news, Caleb’s younger brother, Colten, also crashed in the competition and was taken to the hospital with a separated pelvis.

Colten took to Facebook on Saturday in an effort to thank everyone and assure them that he was OK.

"Thanks everyone for all the prayers and support. I'm out of the hospital and doing good but still sore. Caleb is still in the hospital but is stable and doing good."

Caleb Moore has been active in ATV/Snowmobile Freestyle Riding in the Winter X Games since 2009 and three Winter X medals -- two bronze and one silver.

ESPN+ Video Winter