The former Chelsea man reportedly stormed out of Loftus Road when told he had not been picked to start against Fulham in December and was subsequently fined two weeks' wages.
The 30-year-old was regularly left out of the matchday squad after that but returned to the starting line-up for Saturday's 2-0 home loss to Manchester United.
And Redknapp said: "Jose made a mistake but it can't go on forever.
"The issue is resolved, he was fined and we've all moved on from it. He's trained hard and is showing the right attitude again.
"There's no question he can play. He's good on the ball.
"I took him with us to Swansea a couple of weeks ago and didn't even put him on the bench. I did that to test his attitude and he was fine."
QPR remain seven points adrift of safety but defender Christopher Samba hopes the fact they are being described as relegation certainties could work in their favour.
"There is a big challenge ahead of us," he said. "Other results were good to us (at the weekend), we are still the same number of points behind as we were before the game.
"I do think there was an improvement in our game on Saturday but we need to get going.
"Everybody has written us off and this will take the pressure off us, because nobody expects us to do this.
"We are going to go into the next matches, do our thing and, if we can avoid relegation, it will be the greatest achievement."