On Saturday's starter, and other roster machinations

Stephen Strasburg is pitching tonight's series opener for the Nationals against the Braves. Tanner Roark is pitching Sunday. Which leaves Saturday's starter as the always mysterious "TBA." At least, officially, that's what the Nats are saying.

All signs, however, point to Reynaldo Lopez making the start. The right-hander is scheduled to pitch for Triple-A Syracuse, so he's already properly lined up.

Why are the Nationals going to call up one of their prospects now when the schedule allows for them to wait until Tuesday to do it? Why not just start Roark on normal rest Saturday and then Max Scherzer on Sunday?

The schedule may have something to do with that. The Nationals this weekend are hosting the Braves, owners of the majors' worst record and least-productive lineup. From here, they head out to Coors Field to face the Rockies, owners of the National League's most-productive lineup.

Given the way Lopez has been erratic so far in his two big league starts (both against contenders, the Dodgers and Giants), perhaps the club is trying to create the most-favorable matchup it can.

The logic makes sense, right?

If they do call up Lopez, or anyone else from the minors, the Nationals will have to drop somebody else from the big league roster. You would think that would be a reliever, since they continue to carry eight. Though it's possible they could send down a position player like Brian Goodwin (that's assuming Bryce Harper is healthy and able to play again, of course).

If they go the reliever route, it's awfully tough to envision a scenario in which anyone other than Jonathan Papelbon is worthy of being dropped. Everyone else has either pitched well (Mark Melancon, Shawn Kelley, Sammy Solis, Blake Treinen, Matt Belisle, Yusmeiro Petit) or is under contract beyond this season (Oliver Perez).

So perhaps Papelbon, who at this point has been relegated to mop-up duties, is in danger. Then again, the Nationals have gone this far with him. And with rosters expanding to 40 in only 19 days, there may be motivation to try to just make it to Sept. 1 with as many players still as club property, then use the final month of the season to both evaluate young guys who could win a spot on a theoretical playoff roster (ie. Koda Glover) and stash away underperformers who aren't part of the plan anymore (ie. Papelbon).

The odds of Papelbon being used in any more situations of consequence seem remote. But if you're the Nationals, and you're already paying him the rest of the season, and he's not causing any trouble behind the scenes, there's not a whole lot of harm keeping him on the roster. Provided they don't desperately need his spot for someone else for the next 19 days.