ALLEN PARK, Mich. -- Just after 1 p.m. ET on Monday, there could have been a collective sigh of some relief around the Detroit Lions facility.

It was then, during head coach Jim Schwartz’ weekly news conference, that he said star running back Reggie Bush did not have a long-term knee injury.

So all of the Lions can say it together now: Phew.

“He is certainly an important part of our offense,” Schwartz said. “Our offense was moving very well in the first half. We were converting third downs, converting about 50 percent of our third downs in the first half. Second half I don’t think we converted one.

“So obviously he meant a lot. Calvin (Johnson) was making a lot more plays in the first half because of the dynamic with Reggie. When he went out of the game, we weren’t really able to maintain that.”

And that is going to be the perpetual concern for Detroit. The Lions know what they can be with Bush in the game. It is when he's out the worrying can begin.

Considering how ineffective Detroit’s offense looked without Bush, having tests return clean is about as much of a win as the Lions could hope for on the day after a loss. In two games, it has become fairly obvious opponents were willing to give Bush at least the sliver of room he needed to make plays happen.

“There’s a reason that we went and got him,” Schwartz said. “And that’s because that guy is a very important guy in our offense. I think there’s probably a lot of teams that if they lost that guy, they would say they struggled to move the ball, struggled to do that.”

When Bush went down, the offense wasn’t the same. Not even close. The Lions halved their offensive stars. This is the concern now. For the second straight week, there are conversations about Bush and his injuries on a Monday.

The wonder is his durability. Schwartz said the Lions looked at that when they initially signed him and were encouraged he played and started every game last season. And in reality, his durability for a running back hasn’t been terrible.

He has played in at least 10 games in every season he’s been in the league except for 2010, his last in New Orleans. The past two years, he has come close to or eclipsed 1,000 yards rushing.

So durability shouldn’t be a factor, although having four parts of his body bothered in two weeks is at least cause to raise an eyebrow.

Unlike last week, where there was little question Bush would be available for Sunday, but there is a little bit more of one this week against Washington. The Lions will have to see how Bush's knee progresses -- especially for a running back who relies so much on his speed and his ability to change direction in a snap instead of a bruising back.

So unlike the thumb and even the groin injuries, the knee is a bigger concern. The knee is what makes Bush so special. Without healthy knees, Bush won’t have the agility and explosion he needs to be the back he has been turning into.

The back he is turning into is exactly what Detroit had hoped for. Now, they just need to make sure he’s able to stay on the field.