Holliday was placed on the 15-day disabled list on Saturday, retroactive to July 12. The No. 3 hitter had already missed four games after getting hurt running to first on July 11 at Chicago.
"It was that missing 10-20 percent where he still felt a little something," manager Mike Matheny said. "We just had too many things going in our favor, all the time that's already passed, the break, a day off on Monday."
Matheny didn't want to risk keeping Holliday active to pinch hit, knowing players have a hard time throttling back.
"If it's a big run, it's the last out of the game, when you kick it in gear and you might be safe and we win, how do you not?" Matheny said.
The team purchased the contract of first baseman/outfielder Brock Peterson, a Pacific Coast League All-Star at Triple-A Memphis, in time for Saturday night's game against the Padres. Carlos Beltran batted third.
The 33-year-old Holliday, a career .310 hitter, is batting .268 with 13 home runs and 47 RBIs.
The 29-year-old Peterson was batting .306 and led the PCL with 22 homers to go with 66 RBIs in 93 games at Memphis and is making his major league debut.
"His eyes are spinning a little bit now, and rightfully so," Matheny said. "He's very excited and it's just a great story. But nothing's been given to him, he's had a tremendous season and I think he'll fit in well with what we're looking to do."