Oden will provide them with what they need from him. At most in crucial games Oden will play around 20 minutes. They will rotate between Birdman, Bosh & Oden against the Pacers, Bulls, Clippers, Grizzlies & other teams with dominant bigs. Other teams who don't have dominating bigs, Oden will see probably 10 mins max at most. It's honestly a win/win situation, Oden finally gets a chance at redeeming himself, and the Heat have found another cheap way to get past their problems. I doubt Oden will get enough playing time to honestly hurt himself, though that Trailblazers team was cursed when it came to injuries so I won't hold his durability short. I feel like Oden will be one of the final assets they need since the Heat didn't do well rebounding, and didn't have anyone who could really alter shots at the rim, and with Oden that's your guy. He has a subpar offensive game, but with LeBron Wade & Bosh you don't really need any center with anything above an average offensive game. The contract they are signing him at won't hurt either if he gets hurt, since they still won back to back NBA championships playing mostly small ball anyway.
Also, what Gabe's saying about Rondo makes sense, but not exactly because they are "wasting his talent". They would trade Rondo to deepen their roster, and gain more expiring contracts. Basically if you haven't noticed the Celtics are looking at the new, and are building around Rondo (if they don't elect to trade him), Bradley, Green & Sullinger. The 2014 draft supposedly is one of the best drafts since '03, which is remarkable. With the depth in this draft, if the Celtics could manage a few first round picks & possibly a few mediocre players with expiring contracts they would most likely take it to deepen their team for upcoming years. Anyway you look at it, there is a reason the Celtics have so many championships. They know exactly how to keep rebuilding, and know when it's time to change up the pieces to do so.