The months of May and June are a fairly boring time of year for the NFL. The Draft has concluded and teams are just beginning to sign their draft picks and it's no different for the Lions. They do, however, have a very good track record of getting their rookie draft picks signed before the start of training camp. Over the last three years, only one rookie wasn't signed before the start of training camp, Calvin Johnson. He missed one or two days last year, but that was only because he had a very complicated contract that needed to be written and once it was done, he was at camp. 75% of drafted rookies don't sign a contract until after July 4th. The start of training camp is at the end of July and there is nothing that can be gained by signing rookies at the end of June/early July that they'd lose if they were to sign the week before training camp.
Over the past month the Lions have released seven players and placed one player on injured reserve. This freed up eight roster spots and the Lions will need one more spot before they can officially sign all of the rookie draft picks. On June 17th, the Lions released Darrell Blackman, Justin Sanders and Ronyell Whitaker. On June 23rd, Allen Ervin, Greg Lee, Jonathan Lewis and Buck Reed were released. On the 24th of June, Shemiah Legrande was placed on Injured Reserve and is officially done for the season. None of these transactions had an impact on the Lions salary cap status.