The Cardinals have activated right-handed pitcher Riley O’Brien from the 60-day injured list, the team announced. He has been optioned to Triple-A Memphis. In a corresponding transaction, fellow right-hander Nick Robertson has been designated for assignment.
O’Brien, 29, has been on the injured list almost all season with a right forearm flexor strain. The Cardinals clearly like what he has to offer – he made the Opening Day roster out of camp – but they ultimately decided he is too much of an unknown quantity for a spot in the bullpen right now (per Jeff Jones of the Belleville News-Democrat). Jones notes that the decision for the final spot in the bullpen came down to O’Brien and Kyle Leahy, and the Cardinals were more confident in what Leahy brings to the table. Leahy, 27, has a 3.86 ERA and 4.46 SIERA in 37 1/3 innings this season. O’Brien, on the other hand, has only pitched 3 1/3 innings in his MLB career. His Triple-A numbers were promising last season (2.29 ERA, 3.77 FIP in 55 IP), but it’s understandable why the Cardinals would want to see more from him before throwing him back into their bullpen amid a close postseason race.
Robertson, 26, came over to the Cardinals this offseason as part of the trade return for outfielder Tyler O’Neill. He made eight appearances for St. Louis, pitching to a 4.38 ERA and 2.97 SIERA in 12 1/3 innings. However, he has a far less appealing 7.48 ERA in 21 2/3 innings at Triple-A. If he passes through waivers unclaimed, the Cardinals can choose to send him outright to Triple-A (where he is already pitching) as additional minor league pitching depth.