"Because of an ongoing review of the space shuttle's flow control valves, NASA managers are rescheduling meetings next week to assess the launch readiness of shuttle Discovery's STS-119 mission to the International Space Station. The Space Shuttle Program will hold a meeting Feb. 13 to review data and determine whether to move forward with a flight readiness review on Feb. 18. The official launch date will be set at the readiness review, but for planning purposes launch now is no earlier than Feb. 22."
Shuttle Discovery launch now no earlier than Feb. 22, Orlando Sentinel
"Just in from NASA: The launch of space shuttle Discovery to the international space station has been delayed at least three more days and is now scheduled to lift off from Kennedy Space Center on Feb 22. at the earliest."