For me is that you didn't need to add him to the 40 man roster. We already have him on a minor league deal. This now becomes a major league deal. The FO added him to protect him from the rule 5 draft. You only do that if you already planning to use Singleton at the major league level. (why you would think that anyone else would pick him up in the rule 5 after not playing in the majors for the last 8 years is beyond me).