ABC announced a fall schedule on Tuesday that doesn’t look much different than last year’s, but with one major exception: “ High Potential ,” which has turned into ABC’s signature primetime drama hit, isn’t there. In what may be the most surprising move of the fall, ABC has opted to hold Season 3 of “High Potential” for midseason. (Perhaps they should call it “Hiatus Potential.”) Instead, “R.J. Decker” — which as one of the network’s few bubble shows, narrowly avoided cancellation – will get the primo Tuesday 10 p.m. slot (which had been filled by “High Potential” last fall). Ari Goldman, ABC’s senior vice president, content strategy and scheduling, said the decision to move “High Potential” to midseason came out of wanting to air the show’s entire Season 3 run without a break.…