Kevin Seraphin apparently battled knee trouble all last season. Now, with the year over, he's taking care of it. Via CSN Washington's J Michael.
Seraphin should be fine for training camp, but the injury will sideline him for next month's World Championships, according to FIBA's website:
The procedure appears to be a standard arthroscopy to clean out the kind of wear and tear that often develops in a knee over the course of the season. Michael suggested it became a problem as early as December and resurfaced in March. Seraphin played in just 53 games last season, though many of those were DNP-Coaches Decision.
This may partially explain why Seraphin is sticking around for one more season at a somewhat-hefty $3.8 million salary. The Wizards could believe Seraphin's performance will improve with a healthy knee. Of course, it may not, and there's not a ton of playing time for Seraphin anyway if everyone stays relatively healthy.