Jackson was evaluated Tuesday by a physician, who determined that he had developed an ulcer in his stomach. Jackson's condition will continue to be evaluated, and he hopes to return to action as soon as possible, Mainieri said.
"Obviously, this is a huge disappointment for us because of what Chris means to our team," Mainieri said. "Our primary concern, however, is that Chris overcomes this and returns to normal health. In the meantime, we have to charge forward and rally around the guys who will take Chris' place in the lineup."
The likely candidates to replace Jackson at second base are sophomores Buzzy Haydel and Nicholas Pontiff, and freshman Ryan Schimpf.
Jackson helped lead LSU last weeked to a season-opening sweep of Saint Mary's (Calif.), batting .300 (3-for-10) with four steals, two runs, two walks and one RBI. He was the Tigers' lead-off hitter in Sunday's 6-2 win over the Gaels.
Mainieri also said Tuesday that reserve utility player Chris McGhee suffered a laceration of his right hand during Saturday's game versus Saint Mary's and is out indefinitely. McGhee sustained the injury while making a diving attempt to catch a fly ball.
Jackson out with stomach ulcer
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