Bale to replace under fire Di Maria
Bale hasn't started Madrid's last three matches due to a calf injury, but did make his return as a substitute for the final 25 minutes of Monday's 3-0 win over Celta Vigo.
Angel di Maria was the man to be replaced by Bale and the Argentine controversially grabbed his genitals as he was coming off the field following whistles by the Santiago Bernabeu crowd to his departure.
Real have since opened an investigation into the gesture with Di Maria protesting his innocence and apologising if any unintended offence had been taken.
And whilst Ancelotti confirmed Di Maria wouldn't start against Osasuna, he insisted the reasoning was to give Bale some much needed match practice.
"Tomorrow he will not start because I am going to play a fresher player.
"There is no problem in him playing. He is happy to be here, he is calm and has a good relationship with his teammates. He won't play (tomorrow) but not for this reason.
"We have Bale who didn't play against Celta Vigo and he will start tomorrow."
Rumours have linked Di Maria with a move to free-spending Ligue 1 side Monaco this month.
However, Ancelotti reiterated his stance that he didn't see anyone leaving or arriving at the Bernabeu during the January transfer window, including Manchester United target Fabio Coentrao.
"I have not spoken to Coentrao and Di Maria because there is nothing to speak about. There will be no signings nor sales. We have a very good squad and don't have great injury problems just now so we don't need anyone."
Xabi Alonso will also miss out against Osasuna as he continues to suffer from a burst left eardrum.
The midfielder suffered the injury in the win away to Valencia just before Christmas, but it had been expected he could continue to play without any problems.
However, the Spanish international had to be withdrawn at half-time against Celta earlier in the week because the noise in the stadium was affecting him.
"He doesn't have problems in training but when he hears the noise in the stadium it bothers him. It will improve, although he is not in the squad tomorrow," said Ancelotti.
"He won't have problems playing, but we need to see what it is that he is feeling. Today he will meet with a specialist to try and find a solution to the problem."
Related Real Madrid News