The reliever showed off the delivery on Saturday night against the D-backs with mixed results. He gave up a solo home run to D-backs left fielder Jason Kubel and walked the next two batters, but he also induced a double-play off the bat of Miguel Montero. He retired center fielder Chris Young on a fly ball to right field to get out of the inning.
Two years ago, Del Rosario was 1-1 with a 2.13 ERA in 8 2/3 innings in the big leagues for Cincinnati. He has a 6.57 ERA in 12 1/3 innings with Houston this season.
"We're trying to get it to where he's confident and he's comfortable with it as a lower arm-slot, where he is able to throw strikes," Astros manager Brad Mills said. "Get him to throw the ball like he is capable of throwing."
Del Rosario said Astros pitching coach Doug Brocail and new closer Francisco Cordero, Del Rosario's teammate in Cincinnati, have been very helpful.
"Cordero came to our hotel room last night and talked to me, Fernando [Abad] and [Rhiner] Cruz about forgetting about the past and moving forward," Del Rosario said. "He could see that something was wrong, so he just reminded us to be optimistic. He talked about what happened to him in Toronto and how he is going forward, too. It was a great advice from somebody who has been in the big leagues a long time."
Del Rosario said Cordero had similar chats with Johnny Cueto, Edinson Volquez, Aroldis Chapman when they were teammates with the Reds.