Daniel Joques O'Brien (born April 22, 1954) is a former Major League Baseball (MLB) pitcher.

[5] He pitched in the Cardinals' farm system from 1976–1978 culminating with the Springfield Redbirds, their AAA affiliate in the American Association.

[1][7] His first decision, a loss, came 4 days later when the Cardinals lost, 2–1, to the Phillies at Veterans Stadium.

[8] O'Brien opened the 1979 season back with Springfield before joining the Cardinals in early August.

In 1991, he skippered the Falmouth Commodores of the Cape Cod Baseball League.