The 32-year-old's problem is not serious, but has ruled him out of Sunday's LaLiga match at the Ipurua Municipal Stadium.
Luis Enrique insisted Iniesta's absence would not change anything about Barca's style of play, but does not think there is anyone in his squad or elsewhere who is similar to the absent star.
"His injury will not change anything with our style – regardless of the players we have out there, we always have the same objective," Luis Enrique said at his pre-match media conference.
"But nobody in my squad and nobody in world football is like him. That is the problem!
"I have got excellent players in that position, all of them have the chance to bring something to the team in attack and defence, but I have never seen anybody like Iniesta."
Iniesta has only completed the full 90 minutes on six occasions this season, but Luis Enrique does not have concerns over his durability.
The Barca boss said: "He has finished six games because as coach I have substituted him when I have had the chance to give him a rest given how important he is for us.
"I try to control the amount of time he plays so we can enjoy him as best we can. It is something we try to do not just with Andres but with all the players. We look at the profile of each player and try to control the amount of time they play.
"But at the end of the day football has contact. Contact is legal and sometimes that causes injuries. His first injury this season came from an impact against Sevilla, so he has not had much luck in that aspect.
"But we are working for all the players to be in the best physical shape. In this case it is not a really important injury and he will be back really soon."
Asked if Gomes was in pole position to replace Iniesta, Luis Enrique said: "That is the area where I have the most options in the squad and there isn't one player ahead of the others.
"I have great options, lots of choices in midfield. Who plays depends on the opponent, our performances and the form of the players at each moment. There are a lot of factors."