Which Jersey Numbers Are Not Assigned?

Following the discussion on the previous article Ravens Jersey Number To Retire, I was curious to see which numbers were not assigned for training camp this year. Some might be arbitrary, but others are because of players who wore them previously. After pulling up the Ravens roster, these are the unassigned number, with a listing of the prominent players who wore the jersey number (unless it is obvious why it wasn't given out):

1- Only player ever to wear it was Randall Cunningham

6- No one important has worn it, except in preseason

10- Backup QB's Kordell Stewart, Stoney Case, Troy Smith, Keith Wenning, Eric Zeier

19- Only player to ever wear it was Scott Mitchell

20- Ed Reed

47- Only player of consequence to wear it was Will Demps

52- Ray Lewis

66- Ben Grubbs, Bennie Anderson, Gino Gradkowski, Tony Jones

75- Jonathan Ogden

84- Only player of consequence to wear it was Jermaine Lewis

Interestingly there are 2 players listed as #77, Ryan Jensen and De'Ondre Wesley. Also, #27 is now Asa Jackson.

The only numbers not given for a reason seem to be #20, #52, and #75. I feel that #3 should also be unused, especially since there are several numbers available that work for a kicker (1 & 6).

Other than those 3, it seems we seem to have no problem giving out any other number....