Tiger Woods heads into this week's season-ending Tour Cham­pion­ship in pursuit of a sixth victory of the year as the top seed in the FedExCup standings, yet with a few question marks still hovering over his game.

No-one has come close to his six PGA Tour wins during 2013 but the world No.1 has lost some momentum in the last two FedEx Cup play-off events, his poor putting under­mining his once renowned ­ability to close out tournaments. After getting into prime position in the Deutsche Bank Championship outside Boston just over two weeks ago, Woods fell back into a tie for 65th with scores of 72 and 73 in the last two rounds.

At the weather-delayed BMW Championship in Chicago, which ended on Monday, Woods trailed by just four shots going into the final round but again struggled with his putting as he slipped back into a share of 11th in an elite field of 70.

"I think I had somewhere in the neighbourhood of five to seven three-putts," Woods said of his four rounds at Conway Farms GC where low scores were plentiful. "It was not a very good putting week. You know, it was just one of those weeks where I just didn't have it."

Woods has recorded the lowest scoring average on the PGA Tour this season, with 68.87 but, significantly, he is a lowly 118th when it comes to his average score in the final round, having managed only 71.43. "Eliminate the simple mistakes on the greens, and I would have been all right," the 14-times major champion said of his final round at Conway Farms. "I would have been in there with a better chance. But I'm in good shape going into this week."

Woods is one of just five players in a field of 30 who would secure FedExCup honours, and the mind-boggling bonus of $10m, with victory here. He has a reasonable chance of landing the overall prize with a top-five finish at the Tour Championship, and mathematically could still do so by ending up 29th at East Lake.

"Well, I'm in a position just like the other four guys in the top five," said Woods, who was the FedEx Cup champion in 2007 and 2009. "Top five you control your destiny. You win the tournament, you win it outright.

"Sneds proved that last year," he added, referring to his fellow American Brandt Snedeker, who clinched the 2012 Tour Championship and FedExCup honours after starting the week fifth in the standings. "With the double [points] reset, it's all about positioning. We're jockey­ing for ­position to be in the top five, and I was able to accomplish that."

The other question mark hanging over Woods' game at the moment relates to the rules violation he incurred during the second round of the BMW Championship where he was hit with a two-stroke penalty for a moving ball. What made that infraction stand out was that it was his third this year, but the first where he was still unhappy with the decision even after watching video footage of the incident.

"After seeing the video, I thought the ball just oscillated, and I thought that was it," Woods said. "I thought that was the end of story. But they [the rules officials] saw otherwise."

"They replayed it again and again and again, and I felt the same way."