Day and night: Former world No. 1 Jason Day has had a most forgettable 2017 – no wins and only five top 10s in 19 starts. He recently fired his boyhood mentor who served as his long-time caddie, Colin Swatton. Returning to the event from which he withdrew last year (chronic back issues), Day seemed to be in the process of a significant reboot at this Tour Championship.

He got downright serious at one point Friday, going 4 under through his first 10 holes, and 5 under for the tournament. A stretch of three straight bogeys on the back eventually cooled his jets a bit. Still, Day’s 67 Friday represented his eighth straight sub-par round, doubling his previous longest such streak this season.

“I just feel like if I'm on the fairway I have a really good shot at making birdie,” he said Friday. There’s life left yet in the 29-year-old Aussie.

Wardrobe malfunction: Jason Dufner, who just got in as the 30th player in the 30-man Tour Championship field, supplied some unintended drama Friday. Why wasn't he picking his ball out of the hole after putting out on Nos. 16 and 17? And why, when he did retrieve it on the final hole, did he do it so gingerly. An injury of some sort, perhaps? No. He had split out his britches during the round and was trying to bravely carry on in the face of adversity.

Two words of advice for Dufner as he goes forward: Kale salad.

The battle for 30th: Given all the money that is thrown about this week at East Lake – and why, oh, way, doesn't any of it spill over into the gallery? – there is a certain, possibly warped, fascination with the fellow who finishes last. The one who plays dreadfully – who would have missed the cut and been down the road at any full-field event. Yet, with the unlimited largesse of the Tour Championship, you finish dead last and still earn $315,000 ($175,000 FedEx Cup bonus plus a $140,000 tournament purse). A solo 30th at the Masters, for instance, would pay $74,800. So, who are the leading candidates for the most fortunate worst-of-show of them all? Right now it's Kevin Chappell (8 over) and Rickie Fowler (7 over) in the lead (?) for that distinction.

Breaking up the boys: Friday was eighth time in the last four weeks that buddies Justin Thomas and Jordan Spieth have been paired together in tournament play. It's really time for a break. With Thomas climbing to the top of the Tour Championship leaderboard Friday, and Spieth failing to keep pace, they won't be teeing off within an hour of each other Saturday (Spieth at 1:25, Thomas in the last twosome, launching at 2:35).

Where are the eagles? With only two par 5s on the course, the eagle opportunities are more limited at East Lake. Still, the main reason for flipping the nines here a year ago was to introduce more volatility to the finish. Which, in theory, means more looks at eagle at the end. Neither of East Lake's par 5s has been particularly generous on that score. Through two rounds, they have yielded but a total of four eagles, evenly split between the two. Justin Thomas vaulted into a share of the second round lead with the only eagle of Friday on No.18, and finally demonstrated the potential for something really dramatic this weekend. (Pat Perez holed out on the par 4 16th Friday for the only other eagle of the tournament thus far).