If your shaft is parallel to the X axis, the two bearing supports only constrain Y and Z at two point spaced along X, which together constrain rotation of the shaft about Y and Z.

That leaves two degrees of freedom free:  translation along X and rotation about X. You can support this by picking an end face of the shaft and inserting a Remote Displacement.  Leave all DOF Free but set X = 0 and Rotation X = 0.  Now all six DOF are supported. 

I expect there is no force along X or any moment about X so the reaction force and torque from the Remote Displacement will be close to zero.