The Cardinals are sending struggling Todd Wellemeyer to the bullpen.
Wellemeyer is 7-9 with a 5.79 ERA.
He threw a bullpen session Tuesday and manager Tony La Russa said Wellemeyer will be available for relief duty on Thursday.
The Cardinals plan to recall righty Mitchell Boggs from Memphis to take Wellemeyer's turn against Houston on Friday night.
Boggs has started four times for St. Louis this season and is 1-0 with a 3.22 ERA.