Proper Abbreviation of "Servant of God" in Catholic Writings?

When writing, we may abbreviate "Saint" as *St.* or *S.* (in olden times). "Blessed" as *Bl.* But how, in English, may one abbreviate "Servant of God"? In particular, I would like to make reference to *Servant of God John A. Hardon, S.J.* in something I am writing by shortening "Servant of God" to something that uses two or three letters. Is there a proper way to do this?