Lionel Messi and Sergio Busquets had to rest and that is why they were substitutes against Athletic Bilbao, says Ernesto Valverde.
Messi and Busquets started Saturday's 1-1 draw in LaLiga on the bench, with Valverde having an eye on a trip to Tottenham in the Champions League.
Oscar De Marcos gave Athletic a first-half lead but Messi came on after the interval to rescue his side a point by setting up fellow substitute Munir El Haddadi.
With Valverde beginning to rotate his team - Luis Suarez and Jordi Alba started on the bench for their loss at Leganes last time out - Barca have failed to win their last three games.
And the Barca coach defended his gamble, indicating a busy schedule leaves him with no alternative but to leave his star names on the bench on occasion.
"When I make the decision, I think about what's best for my team and for my club," Valverde told a news conference.
"I always do that before playing games, I can't do it afterwards or rewind.
"Fans can decide what they think is convenient, but I need to think about the best for my team.
"It's my absolute responsibility, we have four games in 10 days [actually 11] and I thought that Leo and Busquets had to rest knowing that we have a very difficult match on Wednesday.
"I knew it was a risky decision, but if it had gone well, you wouldn't be asking me about it."
[MEDICAL ANNOUNCEMENT]Tests have confirmed that has pulled his rectus femoris muscle. He will miss the next match, and his availability after that depends on how the injury develops September 29, 2018
Barcelona have confirmed Sergi Roberto will miss Wednesday's visit to Wembley after sustaining a thigh injury against Athletic.
And Valverde is under no illusions about the challenge facing Barca against the Premier League side, who lost 2-1 at Inter despite taking the lead in their Group B opener.
"It will be a complicated game, like the one we are having," the Barca coach added. "If we win, very good, and if we lose, very bad.
"It is important, because if we win we will take a very important step. They will be tight and it will be difficult for us. We're going to try to win.
"If this affects us for Wednesday, it will be fine. It's a problem, but my team will not lose face in the game.
"I do not know if it's the worst moment. Whenever there is a defeat there is a mess and it is always an opportunity to reaffirm. You always have complicated moments in the season. Let's face it."
