Quentin, who last played on July 30, received the third of three lubricant injections in his right knee in Los Angeles on Thursday.
The club will see how Quentin responds over the next week to 10 days, Padres general manager Josh Byrnes said, before deciding on a next step. But failing significant improvement, there is a real chance that Quentin next will see the field in 2014.
And at this point, with only 41 games remaining in the season, the Padres think their wisest move may well be to give him an extended period of time to heal so that he's ready for next spring training.
"If he feels good within 10 days, we'll let him play," Byrnes said. "But if in a week or 10 days it's not clearly better, then the decision is made for us."
Quentin, who signed a three-year, $27 million extension with the Padres in July 2012, has never played in more than 131 games in a season. He has played in only 82 this year, and he played in only 86 last summer in his first season in San Diego.
Both of his knees are chronically bad, and he missed another eight games in April when he was suspended for charging the mound when the Dodgers' Zack Greinke hit him with a pitch.
Quentin, 30, is hitting .273/.363/.492 with 13 homers and 45 RBI.