Hmm. He's a utility infielder type. He's arguably better than anything we have in the minors to fill that role on the ML roster (e.g., Jose Gomez, Jose Antequera). They're going to have to have another infielder on the 26-man roster (in addition to Kingery, Gregorius, Segura), and it's not likely to be Arquimedes Gamboa. They'll have to clear a roster spot for that infielder, so perhaps there's little reason not to clear that roster spot now.
Not to say that they won't try to upgrade the reserve infielder spot, but hanging on to Machin until they do could make sense.
Oh, and there's also Roman Quinn, who could (arguably) serve as a reserve infielder - of course, putting Quinn in the middle infield is an invitation to the EMTs....