Adam Dunn was placed on waivers by the Nats this afternoon. OH MY GOD!
When people refer to the "trade deadline" in baseball, they usually mean the non-waiver trade deadline, or July 31st. On or before this date, teams can trade players to their hearts content (pending league approval) without sending the player through waivers.
From August 1st through August 31st, players must pass through revocable waivers. (Since players must be on the active roster by August 31st to be eligible for the playoffs, not too many trades are going to happen after that date.) That means, since it is after August 1st and before August 31st, Adam Dunn has been placed on revocable waivers. Meaning that if any team tries to claim Dunn, Rizzo can say "nope" and pull him back. In all likelihood, that's exactly what he'll do.
However, if Dunn passes through waivers and none of the 29 other teams claim him, he is then eligible to be traded just like he was before July 31st. Kapish? Doesn't mean Dunn is going anywhere, but Rizzo is continuing to explore his options, and why not? That is his job, after all.
I hope you've enjoyed our Baseball 302 lecture on trades this afternoon. I'd say this stuff is a bit to advanced to be considered a 101 class. And now I've realized I've spent too much time thinking about the number I just gave this fake class. Ok, so you stop worrying about Dunn and enjoy the Nats (Olsen) and the D-Backs (Saunders) tonight, and I'll stop spending so much time on meaningless banter.