Biasing using constant current source
You can directly ground the Gate, sort of. 

The Gate is where the input signal is applied. If you have a direct short from Gate to ground, the signal is shorted to ground and there isn't anything to amplify. 

BUT

If your signal source has DC continuity, you can connect it between Gate and ground without any problems. 

This signal source might be a transformer or inductor or similar. The DC continuity provides the bias path that the FET requires.