If the whole thing described below doesn't work out, the Wiz could always move Haywood to Houston for Bob Sura's contract ($3.84 million, one year left), John Lucas III ($700,000, two years left), and Steve Nowak ($600,000 and two years). Neither Nowak nor Lucas has good numbers, but neither got much PT either. Sura is a good roleplayer but could possibly retire (he's 34 and missed all of last season with injuries) and give them cap room, Lucas is a poor man's Mike Conley, a good distributor but not a good shooter (they have similar builds as well), and Nowak was right up there with J.J. Reddick as a 3-point shooter in college (both came in and left at the same time). This gives DC more cap room next season if not this season, a dirt cheap by NBA standards backup point guard to develop (and who has good pedigree and is a DC native, coincidentally) and an outside shooter to bring off the bench to stretch the floor who is even cheaper. You'd also be getting them on their rookie contracts, meaning you could extend them an extra year for the same amount (I'm pretty sure). Haywood becomes a reasonably priced backup for Yao to complement/replace Mutumbo for Houston.
Sounds like a decent haul for both sides. It's basically a salary dump for Washington while also picking up a couple of prospects (baseball style trade) while Houston gets another veteran who can help their bench as they have a closing window to make a run past the first round of the playoffs with T-Mac.