Yep. He'll fit in really well in STL.
The title says it all - fighter DJ King signed a 2 year contract extension with the Blues and then promptly got dealt to Washington for prospect Stefan Della Rovere. Della Rovere was captain of the Barrie Colts last season, and racked up 65 goals and 73 assists in 230 GP for them. He also managed to start a fight at the Capitals development camp last week (s/t to @jprutherford for the stats). He appears to be a bit of a scrapper, if not as renowned as King is. Looking at HockeyFights.com's page for him, he has a few fights under his belt, especially in 2007-2008. I obviously don't see him making the team (we're full and we have Janssen), but if he doesn't return to juniors, I wouldn't be shocked to see him in Peoria with the Rivermen next season.
On a Thrashers/link-pimping note, please to read my write up on the Thrashers' defensive holes and who will be plugging them over on SB Nation Atlanta.