I heard that Abreu is progressing slowly and may take a while. I doubt if Campbell is the callup. Personally, I'd take Sogard or Eaton over anyone else (without looking into the overall math right now).
Not sure how they weigh Tolle vs Harrison. Tolle is far superior, but may have an innings limit. If there is no innings limit, they'll roll with Tolle. If Tolle as an innings limit, he'll be used as a opener or in the bullpen at most. Maybe they just go with Harrison due to the previous MLB service time.