Mark's pitch counts and innings totals are the overriding factors. It's hard to limit pitch counts and innings in the majors. To accomplish that, you'd probably have to start him out as a reliever. When the team would want him to start, he wouldn't be stretched out. As pointed out above, in the minors, the team can pitch him any way they want. Service time doesn't always need to be an overriding factor, but given everything else involved, it may as well come into play. Mark has approximately a month of time right now. A month plus 20 days in the minors would allow the team to keep him an extra year. While less important, super-two can also be considered. That would mean leaving him in the minors about three months. Of course, all this service time stuff assumes he stays up for good once he finally gets the call.