You have to specifically send him down the the minors before rollover for his contract to revert to a minor league contract. If you wait until after rollover, it will renew as a major league contract with a salary of $343k.
In order to be called up to the majors, he has to be on the 40 man roster. Having him on the 40 will burn an option year. So if he was already on the 40, the option year has already burned. If you are adding him to the 40 for the first time in order to call him up, then that action itself will burn the year.
Also, if he's out of options, then in order to return him to the minors he will have to clear waivers. So if you do a call-up for a player with no options remaining, you do run the risk of exposing him to waivers unless you plan to keep him on your ML roster next season.