From what I know of Synchronous Reluctance motors, I don't think you can run them without a VFD UNLESS there is basically no load on them. ABB seems to specifically state that SynRM motors are run with VFDs. Reuland seems to say their SynRM motors can be connected DOL but they may have a special rotor construction that allows that. All I can really say is contact ABB and see what they say.
Keith