The American defender will hope to make his first appearance since moving from the Colorado Rapids in the summer when he joins the League Two side.
American defender Shane O'Neill has been loaned to Cambridge United from Cypriot club Apollon Limassol, the League Two side announced Monday.
The move came "a little bit out of the blue," according to Cambridge United CEO Jez George.
"The connection originally came from [manager Shaun Derry] through somebody that he knows, so there’s a good recommendation in the first place, and we’ve got a few contacts, as I said, over in the MLS and we know the league fairly well," George told BBC Radio Cambridge.