At Planck scale, the physical gluon acquires third degree of freedom in the form of scaler potential when the unphysical ghost particle effect disappears at Gribov horizon. Now, relativity demands Lorentz Fitzgerald contraction of Planck scale at light speed of gluon. But that would mean sudden demise of quantum theory. In order to unite relativity with quantum theory, the physical gluon speed instead reduces to zero in any inertial frame and accordingly exhibits mass gap property. For more details, please refer to my preprint http://dx.doi.org/10.13140/RG.2.2.25092.65926