Hollingsworth, 6'5" center from VCU played three seasons in the league in 2009 and 2010 for the Minnesota Lynx and in 2011 for the New York Liberty. She did not play in 2012 due to her commitment to the Turkish national team where she played during the Olympics in London.
Quanitra will join the team in July after the European Championships again, due to her commitment to the Turkish team. General Manager and Head Coach Mike Thibault had this to say in regards to her acquisition:
Although Quanitra will be in Turkey for the month of June with the National Team for the European Championships, we feel that her talent level will improve our roster down the road.
With Hollingsworth now in DC, she adds another young low post player into the lineup in addition to Avery Warley. Kia Vaughn and Crystal Langhorne as of now appear to be the starting players at the center and power forward spots respectively.
Also with the Draft later tonight, this move seems to give a sign that the Mystics will acquire a guard at the 4th spot. Adding another low post player, in particular a young post with her best basketball ahead of her (and Hollingsworth already is in that category) doesn't make sense to me.
UPDATE, APRIL 15 at 12:55 PM: Monumental Network has a video interview with Thibault, and it can be watched here. Thibault continues to tell Guerin Austin, the in-game host for the Washington Capitals NHL team (and the interviewer here) that he is still debating whether to pick up a "wing or a post." But again, he's saying it, hopefully because he has to rather than because he really is debating at this point.