Virtua Tennis 2009 has been pushed into June to give it a bit more polish.
This is according to Sega site administrator RubyEclipse who stated on the forums:
As you may have already noticed, VT2009 has now been pushed back to a June ship date. It's kind of a bummer as I know everyone is looking forward to the game, but believe me when I say it's almost always worth it to add an extra level of polish and make sure the game is top-notch, as opposed to shipping early with problems.
A new release date is expected to be announced soon. We'll keep you posted.