Watch this video:
Notice at 0:57 Balotelli makes a whistle gesture, he is right. Go to 0:12, a whistle noise is made, similar to a referees. Balotelli clearly hears this and does a little trick shot which is done by a couple of players, not necessarily trick shot but just a little shot when they hear the whistle go. He looks like he prepares himself for LA's freekick but then thinks "What" raising his arms. So, I believe Mancini was wrong to take him off.