The Power Girl writer was originally working alongside Keith Giffen on the bi-weekly 'Brightest Day' tie-in, but is now the only writer on the limited series, reports Newsarama.
"It just became a scheduling thing," said Winick. "Keith has a number of projects coming up that required much more time than he had for juggling a bi-weekly.
"It came down to stuff he's got coming up. Stuff we can't talk about yet."