San Diego manager Bud Black said before Wednesday's game that rookies Casey Kelly and Andrew Werner will pitch Saturday and Sunday, respectively, against the D-backs at Petco Park.
Volquez, who has had issues recently with the blister, will have his start pushed back three days when the Padres play host to the Cardinals.
"It's been troubling him over his last few starts, so we felt it was time to let it heal," Black said.
The Padres are off on Thursday, the first of four off-days this month. The team is using a six-man rotation with Andrew Cashner -- who gets the start Friday -- joining Clayton Richard, Volquez, Werner, Kelly and Eric Stults.
Black said the blister has kept Volquez from using his breaking ball in recent weeks, a pitch that Black said might actually be better than his changeup, which is considered a plus-pitch.