Doubtful KHOU would give up Wheel; and if they were, KTRK (or whomever) would already be running promos touting it.
I heard a few months back, from a former Co-worker of mine (who jumped ship to KHOU), that 11 was expanding the 4pm news to an hour this fall. That effectively displaces Jeopardy! from the schedule, so no surprise 13 is picking it up.
11News at 4 must be getting decent numbers from "Ellen" for them to expand the newscast. On the other hand, its possible those viewers are simply sticking around through the news to watch Jeopardy!