Rasmussen is listed as the Rays' probable starting pitcher Wednesday against the Nationals and is expected to work as an opener.
Since being acquired in the May trade that sent Willy Adames to Milwaukee, Rasmussen has made three appearances out of the Tampa Bay bullpen, tossing 3.2 scoreless frames and striking out seven. He'll receive his first career big-league start Wednesday, but the Rays likely won't ask him to record more than six outs before turning the game over to primary pitcher Michael Wacha.