Why ravindra jadeja is called sir?

It's actually a pretty funny story. His former captain, MS Dhoni, started it. It began as a joke on Twitter a long time ago. Dhoni used to post sarcastic tweets praising Jadeja's unbelievable plays. Think of impossible catches or direct-hit run-outs. Dhoni would joke that only 'Sir Ravindra Jadeja' could pull those off. The fans absolutely loved it, and the nickname stuck immediately. It started as a running gag but is now a real sign of respect for his incredible all-around talent.