He got the nickname for his tenaciousness. His ability to be both brash and, as evidenced from last year's championship, a winner is second to none.

But of late, it's been nothing but bad for Brad Keselowski.

Outside of a sub-par, but respectable 15th at Talladega three weeks ago, the defending NASCAR Sprint Cup Series champion has finished 33rd (Richmond), 32nd (Darlington) and 36th (Charlotte).

It's the worst four-race stretch of his full-time career. But this weekend could provide just the break that Keselowski needs. Dover International Speedway was the sight of his last Cup win, taking the checkers at the Monster Mile last September en route the title.

More importantly, though, this will be the first week back for crew chief Paul Wolfe, who was one of seven crew members suspended for rear-end housing violations found on the team's cars prior to the April 13 race at Texas Motor Speedway. And while it's doubtful that even Wolfe could have helped Bad Brad to a top-10 finish in any of the last four races, there's no denying his talents as one of the best crew chiefs in the business.

"I was proud of the way everyone stepped up in the absence of Paul and the guys," Keselowski said. "For the most part, we had a lot of speed in our cars. We missed it a bit in the (Coca-Cola) 600, and that has us in a bit of a hole in the standings. I know my guys, and we will be out with something to prove over these next few races.

"Paul is absolutely chomping at the bit to get back to the track. And going into Dover, this weekend, as the most recent winner there gives us a little confidence, too."

Looking ahead, Keselowski has to be confident going to the next five tracks. He's won at Dover, Pocono and Kentucky; he has two top-threes in his last three starts at Michigan; and given his affinity for road course racing, Sonoma should bring out the best in the Blue Deuce.

But even with everything turning Keselowski's way, there has to be a certain level of concern in Penske's premier camp. Having quality equipment is paramount to success in this business, but there's also something to be said about confidence.

There was no one more confident than Keselowski, Wolfe and the No. 2 team last season. They could do no wrong. But that was 2012. This is 2013. And it's been an unlucky number over the last month for this team. Adversity is knocking, and now it's time for Brad to decide if the team can turn things around and make a good run at another championship or simply chalk this up to a season gone … well, bad.