Robertson (2-1) had a blown save and was the losing pitcher in Saturday's 8-3 loss to the Rockies. The reliever failed to record an out and was charged with four runs on two hits, a walk and a hit batter.
The usually reliable Robertson entered with the Rangers holding a 3-2 lead, a runner on second base and two outs. As rain began to fall, he yielded a run-scoring single to the first batter he faced. After a wild pitch, another RBI single, a hit batsman and a walk, Robertson was removed with the bases loaded. The right-hander, who entered the game with a 0.87 ERA, threw just 11 strikes among 22 pitches.