LOS ANGELES (AP) – The St. Louis Cardinals placed right-hander Riley O´Brien on the 15-day injured list on Sunday, dealing another blow to their reworked bullpen.

O´Brien has a right flexor tendon strain, and the team sent him back to St. Louis for additional tests. The IL stint was made retroactive to Friday.

The 29-year-old O’Brien allowed one run and one hit in the seventh inning of Thursday’s 7-1 loss at the Dodgers. His arm tightened up on Friday.

O’Brien was acquired in a November trade with the Seattle Mariners. He made the big league team after working 10 innings during spring training with a 0.90 ERA.

The Cardinals are also without right-hander Keynan Middleton due to a right flexor tendon strain.

St. Louis called up left-hander John King to fill O’Brien’s spot. King, who was acquired in a July trade with Texas, was 1-0 with a 1.45 ERA in 20 appearances for the Cardinals last season.