Detroit Lions running back Reggie Bush was optimistic that he won’t miss any time with the injured left knee he suffered in Sunday’s 25-21 loss to the Arizona Cardinals.

“I’m not too concerned” Bush said. “We’ll see how it goes tomorrow and take it one day at a time. I’m not too concerned though. I think I’ll be all right and I’m going to do everything I can to get back on the field Sunday even if I have to rehab 24 hours a day.”

Bush took a helmet to his left knee with just under six minutes to play in the second quarter Sunday and played sparingly after that.

The Lions managed just 90 yards of offense in the second half with Bush mostly on the bench.

Bush played two snaps in the third quarter running for 7 yards on his first carry and fumbling a handoff on the second.

He said the fumble was a product of his injury.

“I wasn’t myself” he said. “I was reaching for the ball. It was 100 percent my fault and like I said I probably shouldn’t have been in there.”

Lions coach Jim Schwartz said Bush who suffered minor knee thumb and hip injuries in last week’s win over the Vikings will undergo an MRI on Monday. Bush was cleared to return for Sunday’s second half but Schwartz said “he just didn’t feel like he could explode off of that leg.”

The Lions signed Bush to a four-year $16-million free-agent deal this off-season with the idea that he would diversify their offense.

He had 191 yards from scrimmage against the Vikings and 25 more rushing and 44 receiving Sunday.

Bush played all 16 games last year with the Miami Dolphins for the first time since his rookie season of 2006.