The big news in NASCAR this week is Dale Earnhardt Jr. will not be competing in the upcoming NASCAR Sprint Cup Series events at Charlotte Motor Speedway and Kansas Speedway after being diagnosed with a concussion.

Earnhardt, driver of the No. 88 Chevrolet for Hendrick Motorsports, was diagnosed Wednesday afternoon in Charlotte.  New York native Regan Smith will be the team’s substitute driver at Charlotte and Kansas.  Smith qualified 26th for tonight's race at Charlotte but was second fastest in yesterday's final practice session.

In other related news, Kurt Busch leaves the Phoenix Construction No. 51 to replace Regan Smith in the Furniture Row Chevrolet.  Busch was signed to drive the No. 78 in 2013 and the final six races of 2012.  Smith appeared to headed to the No. 51 in a driver swap, but now that he is subbing for Dale Jr. in the No. 88, AJ Allmendinger got the call to return to the Sprint Cup Series in the No. 51.

Greg Biffle set fast time in qualifying for tonight's race at Charlotte and will be starting on the pole for the 3rd time this season.  Mark Martin, in his 850th career start, will roll-off alongside of Biffle on the front row.

Here is the complete lineup.