ESPN's Buster Olney reported this afternoon that the Nationals placed Adam Dunn on waivers today.
Don't get too worked up about that; here's a quick primer on what it means.
If Dunn was placed on waivers, he would have been placed on revocable waivers, meaning the Nationals can dangle him to see what kind of interest there is in him, pull him back if he is claimed, and try to work out a trade if a team claims him.
If no team claims Dunn, he could then be traded to any team. It's a procedural move, one made by every team in the league with almost every player on its roster. It buys the Nationals more time to try and trade Dunn, while also giving them a sense of which teams are still interested in the first baseman.
Waiver claims go in inverse order of the standings, starting with the league where the player currently plays, meaning all teams in the NL would get a shot at Dunn before the AL. Because most of the rumored interest in Dunn came from American League teams, it leaves a fairly narrow market for waiver claims on Dunn. He is still owed upwards of $3 million, so a team isn't going to claim Dunn without a good reason. Olney mentioned the Giants and the Rockies, the latter possibly to block the Giants from getting the first baseman.
Essentially, if the Giants - or any other team - put a claim in on Dunn, they would have 48 hours to work out a trade with the Nationals. The Giants were one of the teams rumored to be interested, but general manager Mike Rizzo said he didn't get an offer before the deadline that convinced him it was worthwhile to part with Dunn, who is a free agent after the season. If there wasn't an enticing enough package before the deadline, when any team could make an offer, it seems unlikely there would be a post-July 31 offer that would get the Nationals to trade their cleanup hitter.
So essentially, this shouldn't be treated with surprise or panic. It remains unlikely Dunn is leaving in a trade, though it is worth monitoring.