Pizarro, 39, who has won six Bundesliga titles in two spells with Bayern, featured in four matches under Gareca during Peru's successful World Cup qualification campaign, although the veteran striker's last appearance came as captain in a 1-0 defeat to Uruguay in March 2016.
Peru looked unlikely to qualify at that stage, but Gareca inspired a remarkable turnaround and La Bicolor finished fifth in the section, before edging past New Zealand by a 2-0 aggregate scoreline to book a place in Russia, where they will face France, Australia and Denmark in Group C in a first outing at a global showpiece since Spain 1982.
Watch: Pizarro produced this stunner for Werder Bremen way back in 2001!
"Claudio Pizarro has every chance [of featuring at the World Cup. It all depends on him," Gareca told bundesliga.com. "The doors certainly aren't closed for him.
"We've always analysed Claudio's current state. We've already talked to him and the important thing for a player of his age is to take things day by day. It's entirely feasible that we take him to a training camp to assess what state he's in.
"He's an excellent professional. We have to see what state he's if he's called up. We need to keep track of the latest, how often he's playing, this injuries. All of that affects performance."
Pizarro joined Cologne on a free transfer in September and has since featured six times in the Bundesliga, although is yet to score. Prior to Peru's play-off against New Zealand, he told bundesliga.com that he would like to feature for his country if they reached Russia.