Why speedster Mayank didn't touch 150 clicks on debut vs Bangladesh?

Mayank Yadav made his T20I debut for India against Bangladesh but didn't hit his usual 150 kph speed due to caution post-injury. Aakash Chopra noted Mayank's control and potential despite the lower speed. In his impressive debut, Mayank had figures of 4-1-21-1 as India secured a 7-wicket win, leading the series 1-0.