The Nationals dealt Nate Karns to Tampa for backup catcher Jose Lobaton.
The Nationals acquired a minor league right-hander in exchange for the enigmatic Rodriguez.
In recent weeks, three pitchers have debuted for the Nats. A fourth -- one with big league experience -- is also rejoining the squad.
The rookie right-hander will make another start on Sunday, a combination of his strong debut and Detwiler's lingering oblique strain.
The Nationals could call up reliever Erik Davis following tonight's game for tomorrow, so long as Ross Detwiler is healthy.
By the end of the week, the Nationals will start bringing the bullpen competition into focus.
The Nationals' minor league pitcher of the year makes his first spring training appearance and impresses with two scoreless innings.