There are so many storylines swirling around the Lake Forest fairways that it is hard to know where to start. Arguably the most intriguing – away from the tournament scoreboard and FedExCup configurations – is that surrounding former world number Jason Day.

The 29-year-old Australian was playing for the first time since making a caddie change, sacking his childhood mentor, coach since he was 12 and now ex long-time bagman Col Swatton for an old golf academy mate, Luke Reardon.

The shock move followed two other highly publicised recent player-caddie splits: Phil Mickelson and Jim “Bones” Mackay (after 25 years together) and Rory McIlroy and J.P. Fitzgerald (nine years). Mickelson and McIlroy each have just one top-10 place since making the change but Day, who has dropped to ninth in the world rankings and hasn’t won since last year, can’t afford the same luxury if he is to keep his season going: at 28th on the FedExCup points list, he needs a good finish to secure a place among the top-30 qualifying for next week’s Tour Championship grand finale.

He made an excellent start. “You never know whether you’re going to jell well or not at all,” Day said after making six birdies and an eagle, and one bogey, despite dealing with a sore back. “[Reardon] is one of my best mates, but we’ll be on the course together and I could completely hate him as a caddie. You don’t know until you actually do it… Luke did a fantastic job out there today. I know that he’s a good golfer, got a good, keen eye for the golf IQ, more-so with the actual course management. I think it was a good start.” 

On the eve of the tournament, Day had revealed to the press that Swanton was shocked and disappointed. “He needed some time just going over things and really understand my feelings and what I wanted to try to accomplish in my career as a player, and then obviously trying to get his feelings as well,” Day said. “It’s always hard because we’ve been a team for so long. We’ve been really tight and being so close for very long and we’re still close.”

Day said the chemistry between the two as player and caddie had begun to sour as his game floundered, with just four top-10s this season through the Dell Technologies Championship.

Day found himself blaming Swatton for things the caddie couldn’t control, and they started to not talk to each away from tournaments – thus putting their close relationship at risk.

“Everything is great when you win, but when you’re playing poorly, that’s when a true test of a relationship actually happens between a player and a caddie,” Day said. “It’s more my fault, really, because he’s out there trying to do the best job he can and, unfortunately, sometimes it just doesn’t work out no matter how hard he works. The positive vibes and the positives he’s trying to put out and all the numbers that he can get and information he can get sometimes just doesn’t work out.”

Day stressed that Swatton was “not out of my world one bit… He’s always going to be my coach, always will, unless he gets paid more somewhere else. I’m planning on trying to keep him around. I don’t want anyone else to get coached by him because he’s a really good coach.”

He said the plan was for Reardon to be a long-term solution, although he didn’t rule out the possibility of re-hiring Swatton. “It may be somewhere down the road where four months from now – I don’t even know how long it will be – but I can come back to him and say, ‘Look, man, I made a mistake and I need to come back and have you on the bag'.

“Obviously, I know there’s a relationship there and me and him have been inseparable since the day I came out. Once again, he’s my coach and always will be. I love him so much. I just want to make sure I did the right thing. Obviously, when you let go of someone sometimes it’s hard, but there’s been a lot going this year.”

 

So to the tournament itself… Fellow Australian Marc Leishman led the way after the first day with a nine-under 62, two shots ahead of joint second-placed Day.

Leishman has a putting green in his backyard in Virginia and he mows it religiously. It’s cathartic for him, mowing tight, clean stripes in the Bermuda grass. “I almost like doing that more than I like playing on it. My neighbour thinks I’m crazy. I’m out there every day.”

Leishman’s form on the greens has been topsy-turvy this year. The 33-year-old putted well early, winning the Arnold Palmer Invitational for his second tour victory, but then hit a lull. “I have a tendency to push the putter into the ground. My coach (Denis McDade) picked it up and I started making putts again.”

After finishing third at the Dell Technologies Championship at TPC Boston, Leishman didn’t touch a club last week. He came to Conway Farms feeling fresh, and got off to a great start with seven birdies in his first 11 holes. He thought about the prospect of shooting 59, but pushed it to the back of his mind. “When you start thinking about the score before you finish,” he said, “that generally doesn’t end well.”

 

As for the tournament within a tournament… The top-30 in the FedExCup after this week will have a mathematical shot at the $10 million bonus, but the odds are significantly higher depending on their position in the standings. The top five players – Jordan Spieth, Justin Thomas and Dustin Johnson already are assured that position – would only have to win at East Lake to claim golf's richest prize.

Paired with his two immediate rivals, Spieth carded a 65, while Thomas shot a four-under 67 while Johnson fought hard for an even-par 71.

Currently fourth in the standings, Hideki Matsuyama carded an opening one-over 72, while fifth-placed Jon Rahm had a 69 for a share of 36th place in the 70-player field.

Players facing an exit from the finals series after this week’s tournament, unless they shoot particularly low in the second round, include last year’s FedExCup champion Rory McIlroy (72), Sergio García (68) and Henrik Stenson (72).