Though 2K Sports has yet to make officially announce them the demos for both MLB 2K11 and Top Spin 4 are scheduled to hit the PS3 and 360 on Tuesday March 1st. No details on what the demos will feature yet but that will likely be detailed laid out today.
The arrival of the demo for MLB 2K11 comes one week before its release date while it will be two weeks in advance for Top Spin. The Xbox Live Marketplace generally updates early in the morning at about 2am PT while PSN updates in the late afternoon around 3pm PT.