So who is Regan Smith?

Regan Smith has suddenly vaulted from a driver seeking a full-time ride for 2012, to driving the most well-known car in the NASCAR Sprint Cup Series. Smith, 29, originally planned to drive the No. 51 Phoenix Racing Chevrolet that has been driven by Kurt Busch this season. Instead, he'll be driving the No. 88 Hendrick Motorsports Chevrolet of Dale Earnhardt Jr., who is sidelined for the next two races after suffering his second concussion in the last six weeks. Earnhardt Jr. was caught up in a 25-car pileup at Talladega Superspeedway last Sunday. He was diagnosed with a concussion on Wednesday, leading to the driver change in the car. Earnhardt Jr. said he suffered an earlier concussion in a crash during an Aug. 29 tire test at Kansas, but that it went undiagnosed until Wednesday. Smith has been a regular in the Cup series off and on since making his debut in 2007. He ran seven races that season, ran full-time for Dale Earnhardt Inc. in 2008, then part-time for Furniture Row the following season. He raced full-time for Furniture Row Racing from 2010 through the race last Sunday. It was announced that week that he would part ways with the team at Talladega, setting up the planned ride with Phoenix this weekend. Smith is best-known for winning the Southern 500 at Darlington Raceway in 2011, his lone Sprint Cup victory. But he enjoyed racing success before that. In 2008, he was the Cup rookie of the year. In 2000, he was the USAR Hooters Pro Cup rookie of the year. He's enjoyed some titles as well, winning the 1999 Allison Legacy Series championship. He also won the 1996 WKA Grand National championship when he was 12. Smith began competing in the Nationwide Series in 2005,running the full schedule in 2006. But he's been racing pretty much his entire life. He began racing quarter midgets when he was 4 and worked his way through the ranks. He made his NASCAR debut on Oct. 20, 2002, in the Nationwide Series and also made two Camping World Truck Series starts. Overall, he has 161 starts in the Cup series with the one victory. He has eight top-10 finishes, three of them top-fives, and is a career-best 23rd in the standings at this point. In the Nationwide ranks, he has 102 starts. He has six top-10 finishes, three of them top-fives. In the Truck ranks, he has made 23 starts with five top-10 finishes, one of them a top five.