Washington Redskins star DeSean Jackson sustained a shoulder injury in practice, which could make him miss around 14 days of training camp, coach Jay Gruden confirmed to media outlets. 

A few days ago, Jackson proudly declared that no one in the league - not even NFL's top cornerbacks Darrelle Revis of New York Jets and Richard Sherman of the Seattle Seahawks - can guard him on the field.

But something else was able to stop him. The 28-year-old football player was performing a one-on-one drill when he "had caught a pass and hit the ground and then slid into a sled," reported ESPN. 

"It was the impact of when I hit the ground... It's an unfortunate situation. I was just playing and trying to compete and just had a freak accident," Jackson was quoted as saying.

The Redskins receiver remains optimistic, though, even if he's in a lot of pain. His goal is to recover from his shoulder sprain before the season starts. 

"It's very painful. Being in camp now, I have time to heal it. I'll take the steps to better myself so when I get out here, I can be all right to play... It's hard to do certain movements, so I just need to strengthen it," he added.

Jackson is an integral part of the team. The California native has a record of "13 catches for 40 yards or more," wrote ESPN, something no other wide receiver ever came close to. He also tallied an average of 20.88 yards per catch, three yards more than the next best receiver's record. In 2013, he posted impressive receiving stats of 82 catches for 1,332 yards and nine touchdowns with the Philadelphia Eagles.

Meanwhile, cornerback DeAngelo Hall will also be absent from the camp for a week as he suffered from a groin and knee injury on Thursday, according to NFL.com.