The Detroit Lions received another bit of welcome injury news Friday night.According to NFL insider Jordan Schultz, rookie linebacker Jimmy Rolder did not suffer a severe injury after leaving Fridays training camp practice with a leg issue. Rolder is expected to miss some time, but the injury is not considered major.For a young player trying to earn a role in Detroits defense, any absence matters. The early indication still qualifies as a relief.Jimmy Rolder Avoids Major InjurySchultz reported that sources described Rolders injury this way:didnt suffer a severe injuryHe added that Rolder will:miss some time,Those two details tell the story.Rolder may lose valuable training camp repetitions, but the initial report suggests the former Michigan linebacker avoided the type of injury that could threaten his rookie season.Missed Time Still MattersRolder entered camp with an opportunity to make an impression in a competitive linebacker room.Every practice gives a rookie another chance to show he can handle defensive assignments, contribute on special teams and earn the trust of Dan Campbells coaching staff. Missing time could slow that process, especially with preseason games approaching.The good news is that Rolder should have another opportunity once he is cleared to return.Detroit would much rather manage a short-term absence than begin preparing for life without him.Bottom LineJimmy Rolder is expected to miss some practice time after suffering a leg injury Friday, but the injury is not believed to be severe.That is encouraging news for the Lions and for a promising rookie still fighting to establish his place on Detroits roster.