Calvin Johnson was on the field catching passes and running routes Thursday, continuing the one-day-a-week practice regimen he has been on most of the year. And as Johnson closes in on the Lions’ all-time receiving record — he’s 40 yards shy of breaking Herman Moore’s mark of 9,174 yards, which should fall Sunday against the Eagles in Philadelphia — he said he hasn’t thought much about his ailing right knee and whether the injury might cut short what should be a Hall-of-Fame career. “I’m not worried about that,” Johnson said. “Like I say, when the time comes, I’ll know. But it’s not here right now.” Johnson, 28, set a single-season NFL receiving record last year while missing large portions of practice during the season because of a sore left knee. He suffered a sprained right knee in a September win over the Bears, missed a game the following week against Green Bay and, according to last week’s Fox broadcast, has since been having fluid drained from his knee. Despite the injury, which he appeared to aggravate late in last week’s win over the Packers, Johnson is amid another season that can only be described as special. He leads the NFL with 1,299 receiving yards in 11 games, his 12 touchdown catches are tied with Jimmy Graham for most in the league, and earlier this year he torched the Dallas Cowboys for 329 yards, the most in a regulation game. “He’s amazing, man,” receiver Nate Burleson said. “I brag about him to his face, I brag about him to my family and friends. When you guys are watching the highlights and watching it live, I do the same thing, not only on the field but off the field, too. These moments are very fleeting, which is why I try to embrace them day by day, because when it’s gone it’s gone.” As for topping Moore, Johnson said he hasn’t taken time to reflect on the record, which he’ll eclipse in his 104th career game.