The Catalan giants travel to Paris for their UEFA Champions League quarter-final first leg on Wednesday, but the hosts could be without up to four regular first-team starters.
Former Barca man Zlatan Ibrahimovic is suspended, as is Marco Verratti, while David Luiz (hamstring) and Thiago Motta (thigh) are injured.
Barca have full-back Dani Alves missing, also through suspension, and Luis Enrique says PSG's absentees cannot be allowed to become a distraction.
"They have players missing, that can't be hidden, but remember the group stage game when Ibrahimovic wasn't playing and they beat us [3-2].
"When he did play, we won [3-1 at Camp Nou]. They're important players, no doubt about that, but they've got a deep squad and they're going to create complications for us."
Back in September, David Luiz, Verratti and Blaise Matuidi were all on target in PSG's home triumph in Group F, and the Barca coach is well aware his players cannot afford similar lapses at the back.
"That was not a great game as far as the result was concerned but we came close to the draw," Luis Enrique added.
"We can improve on that, on certain aspects. Particularly in defence we need to improve tomorrow.
"They've got a very, very good team. They're one of the candidates for the title and they beat one of the other candidates [Chelsea, in the last 16].
"It's going to be an open game and I think very entertaining."
Luis Enrique also refused to be drawn on questions concerning Neymar, who reacted angrily to being substituted during Saturday's 2-2 draw with Sevilla.
"I understand that all players want to play and the players should have to understand I have to make decisions," he said.
"From there, you can speculate whatever you want."
