The Barca captain had to be substituted in the first half of Sunday's 1-0 LaLiga win against Atletico Madrid with a hamstring injury.
Iniesta is expected to miss Barca's league game at Malaga on Saturday and Valverde is unsure whether the midfielder will be available to face Chelsea, with the sides tied at 1-1 after the first leg.
"He is training separately at the moment," Valverde told a news conference. "Obviously we do not want to rush things, it's too early to say if he will be available for next week.
"We have similar players, although he is unique. We have similar profile players, Denis [Suarez] and [Philippe] Coutinho, Andre Gomes as well.
"Their characteristics are comparable and they could play in [Iniesta's] position."
Ousmane Dembele is a contender to fill in too, although the former Borussia Dortmund winger has struggled to settle since joining Barca, with his campaign disrupted by injury.
"Tomorrow's game, any game - it's good for a player," Valverde said. "Of course he needs to play so we need to see, but we have high expectations of him as a player.
"Dembele likes to take players on, he's a dribbler and a power player who likes to break into space, he has the ability to do this. He has a lot of virtues.
"He is 20 years old and there are things for him to fine-tune over time. With experience, he will start to perfect areas."
Barca defender Gerard Pique has been battling a knee injury but Valverde indicated the Spain international will play against Malaga and is available for Chelsea.
"If he couldn't train it would be a bad sign, but he is completing training," Valverde said.
"There is no problem with managing the situation, it's a question of asking him how he feels.
"It's a light injury, bothersome maybe. It's more of a knock."