Dr Gridlock has added this to his blog entry, concerning trains to the Nats matches:
'From Dr. Gridlock: WP, the extra Green Line trains will run up only as far as L'Enfant Plaza and not to Gallery Place. And yes, that's likely to be messy. Metro will be announcing many more details, and I'll post them.'
Link to full comments page:
http://blog.washingtonpost.com/getthere/2008/05/the_weekend_and_beyond_14.html#comments (the above is currently about 2/3 of the way down). Nothing new on Nats or Metro sites as yet.