PHOENIX -- A day after left fielder Conor Jackson strained his right hamstring making a catch in San Diego, the D-backs placed him on the 15-day disabled list Monday hours before playing the Cardinals at Chase Field.
Jackson was replaced on the 25-man roster by right-handed reliever Esmerling Vasquez, who was recalled from Triple-A Reno. The move gives Arizona 13 pitchers, eight in the bullpen.
"We're going to go with the extra pitcher at least until when we feel better about where the pitching is," said D-backs manager A.J. Hinch, whose club has lost four in a row, three of them because of collapses by the bullpen.
Jackson, batting .267 with no home runs and two RBIs in 11 games, underwent an MRI on Monday, which revealed no significant damage.
"[The doctors] are not overly concerned that he would miss more than a week, a week and a half," Hinch said. "But we're not afforded the luxury of playing short for that long either from the pitching side or the position-player end of things. He'll probably be ready to return before the time period is over."
Considering the fact that he missed most of the 2009 season battling valley fever, Jackson called the latest turn of events "frustrating."
"I missed most of last year and 12 days in I'm already on the 15-day DL. So this is pretty disappointing," Jackson said. "Im not going to sit here and mope on it. I'm going to get better, get back out there and try to help the team. I'm going to rehab my butt off for the first 10 days and for four or five days after that do some work down in Tucson in extended [spring training]. Then I'll rejoin the team in Houston [on May 3]. At least that's the plan."
Jackson injured himself lunging awkwardly to make a catch on Sunday to end the Padres' five-run seventh inning in a 5-3 loss.
Jackson is already the second regular the D-backs have lost this season. Catcher Miguel Montero injured his right knee running out a grounder on April 10 and had to have surgery to repair a torn meniscus.