you must make it clear that the employee will be moved back into his previous role if either you or he is unhappy with the fit. This will prevent any unfortunate misunderstandings. The trial period is not just for his benefit; it is also for yours. If, after the trial period is over, he loves the role but you perceive a misfit, your assessment wins. He may not be happy with this, but at least he will not feel ambushed.
