3:37pm: The Nationals tentatively plan to call Strasburg up at home against the Pirates next month, writes MLB.com's Bill Ladson. No date is set, but we'll get five or six days of notice before the start. The Nationals host the Pirates June 8th-10th.
10:18am: A source close to the Nationals supports Heyman's note below - June 4th is unlikely for Strasburg's debut. Instead, expect him in the middle of June or even toward month's end. Of course, the Nationals don't mind the extra ticket sales resulting from the June 4th rumor. - Tim Dierkes
WEDNESDAY, 8:41am: SI's Jon Heyman tweets that mid-June is a better guess than June 4th for Strasburg's debut, given the pitcher's target of 100 big league innings. A June 4th debut would project to 22 Major League starts for Strasburg, which would probably put him over that target. Of course, the Nats could shut him down in September if need be.
TUESDAY, 6:07pm: It's looking more and more like Stephen Strasburg will debut against the Reds on June 4th. Adam Kilgore of the Washington Post writes that Strasburg will start this Saturday at Triple A. If all goes well - and that 0.99 pro ERA suggests it will - the Nationals could call on the prospect to open their homestand next Friday. GM Mike Rizzo told Kilgore that the club has not yet decided when to call up Strasburg.
Calling Strasburg up next Friday would give him five days of rest and ensure that his first two starts are at home. Just as importantly, Strasburg would have next to no chance of becoming a super two player after 2012. A June 4th callup would prevent Strasburg from picking up more than 122 days of service time this year and would reduce the chances that he goes to arbitration four times. Since arbitration-eligible players cost much more than the MLB minimum, it's in the Nationals' best interest to prevent their top prospect from becoming a super two.
Strasburg could make his debut against the Reds, maybe even against Mike Leake, who was also a top-ten pick in last year's draft. The Reds would have to skip someone in the rotation for the two youngsters to match up, but with Homer Bailey injured, Dusty Baker could decide to do just that. Strasburg's debut should be memorable no matter what, but imagine seeing him begin his major league career against another pitcher who had no pro experience a year ago.