Stephen Strasburg will throw a side session today, beginning the process of routine work after the first start of his rehab assignment on Sunday. If all goes well for Strasburg today - and by all accounts, he felt fine after throwing 31 pitches for Single-A Hagerstown on Sunday - the Nationals should make a decision on where he'll pitch next.
Strasburg is slated to start somewhere on Friday, with the likely spots being either Single-A Potomac or Double-A Harrisburg, who are both home this weekend. Strasburg began his minor league career at Harrisburg last year, and it wouldn't be surprising to see them send him back there for two reasons: they've had an ongoing tiff with the ownership group at Potomac over the condition of the playing field at Pfitzner Stadium (remember, Strasburg didn't pitch there last year either), and putting him in Woodbridge, just 20 minutes south of Nationals Park, would invite a greater media crush than he'd be likely to see at Harrisburg.
He could also drop back down to the Single-A level on Aug. 17, with both Potomac and Harrisburg on the road, so it might make sense to get him another start at Double-A now, before moving him back there later in the month. But there's also something to be said for a lower level of competition in the early stages of his rehab, where Strasburg is still phasing pitches back into his repertoire.
Whatever the destination, we should know more later today. I'd expect Strasburg to aim for something like three innings and 45 pitches on Friday; think of the progression like a starter early in spring training. If all goes well, he should be ready to pitch five or so innings in the majors early next month.