Eddie Griffen was a 1st round pick. 1st round picks have guaranteed contracts. Anyone picked in the 2nd round is not guaranteed, and thus have to be signed.
You still have to sign them. 'Guaranteed' contract only means that if you terminate the contract, they still get the money. There is a range avalable to each draft position. I believe that the cap figure for each unsigned player is less than the max avalable for that player. By not signing the pick until later, therefore, you would give yourself a slight cap advantage. This would be more critical for someone like the Rockets who are under the cap by just a little bit. Adding a small degree of cap space would have more of an impact.
http://www.chron.com/cs/CDA/story.hts/sports/bk/bkn/1042649 Dawson said he expects to pick up the option on a fourth season of forward Kenny Thomas' contract and to sign rookie Eddie Griffin this week. Dawson plans to add one more frontcourt player before training camp next month, but he said no decisions have been made about whom the Rockets would pursue with or without the exception.
