Detroit Lions RB Sione Vaki exits Thursday practice early with injury

The Detroit Lions were on the field for their latest practice of training camp on Thursday morning and saw rookie running back Sione Vaki exit early due to injury.

According to Tim Twentyman of DetroitLions.com , Vaki suffered a shoulder injury during the session and did not return after exiting. The extent of the injury remains unknown as of this writing.

A fourth-round pick of the Lions earlier this offseason, Vaki impressed during the offseason program and has continued that showing in training camp. He's currently battling for the No. 3 running back role against Craig Reynolds, although he figures to ultimately settle in as the No. 4 out of training camp.

According to Pride of Detroit's Erik Schlitt , the injury occurred halfway through the practice after Vaki collided with a defender during a one-on-one drill. He left the field under his own power.

Rookies missing time during training camp is never ideal, as it can slow the player's growth ahead of their first season. It goes without saying that Vaki's chances of surpassing Reynolds will take a serious hit if he has an extended absence.

It has been a rough week for the Lions when it comes to injuries, as the team has lost defensive lineman John Cominsky to a torn MCL and offensive lineman Netane Muti to an unspecified shoulder injury. Both will require surgery, head coach Dan Campbell revealed.

Muti has since been placed on injured reserve, which will end his season before it starts. The Lions have not placed Cominsky on IR, though, as the team hopes to get him back for the playoffs.