There is an interesting variation between the mohommads of India and Pakistan.
India had Mohommad Azharuddin. No one called him Mohommad, even though it is comparatively shorter. Everyone calls him by the names of Azhar, Azzu, Azza, etc.. Then there is Mohommad Kaif. Everyone calls him as Kaif. Even his parents don't call him by the name of Mohommad.
Pakistanis have Mohommad Sami. And he is known by Mohommad. I haven't heard anyone calling him Sami.