"The last 40, 50 at-bats have gone the other direction," said Padres manager Bud Black.
Cabrera, who has hit either first or second this season, entered play hitting .225 this season with a .102 average in June.
This is the first time Cabrera has hit eighth since 2012.
Cabrera hit a career-best .283 last season and was the team's lone All-Star representative but missed the final 50 games of the season after testing positive for testosterone.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.