The Athletics transferred Andujar (abdomen) to the 60-day injured list Saturday.
Manager Mark Kotsay said Wednesday that Andujar will miss the rest of the season as a result of his core-muscle injury, Martin Gallegos of MLB.com reports.
The Athletics placed Andujar on the 10-day injured list Wednesday with a core-muscle injury.
Andujar is out of the lineup for Tuesday's game against the Reds.
Andujar is not in the lineup for Sunday's game against the Brewers.
Andujar went 2-for-4 in a win over the Rays on Thursday.
Andujar went 2-for-3 with a double, a walk and a run in a loss to the Mets on Wednesday.
Andujar is out of the lineup for Sunday's game against the Blue Jays.
Andujar went 3-for-5 with a solo home run in Sunday's 8-5 loss to the Angels.
Andujar went 3-for-4 with an RBI single and a run in a win over the Angels on Saturday.