The changes were announced on Tuesday, two days before the start of the Abu Dhabi HSBC Championship, one of the main tournaments on the European Tour schedule.
Given he has spent so long away from the course, Koepka is paying little heed to his status as the game's best player.
"I know if I'd been in his situation I would have been as nervous as hell", the world's top-ranked player told BBC Sport. "I mean, I missed competition". "And there's numerous times out there that our group is waiting for people to go, and so I certainly don't want to be waiting on players".
"But I drove the ball well, controlled the ball flight and controlled the distances really well and that's what you have to do out here".
"The first day I picked up the club, same thing, felt like I hadn't left", Koepka said.
"It feels good to be back", Koepka said after his round. "It was a little sore last night, just did some treatment on it, that's expected".
Koepka lines up alongside the two men who won the last three editions of this event, in Fleetwood and Lowry, for the first two days, while World No.6 Patrick Cantlay makes his European Tour debut in a trio with Garcia and three-time Rolex Series victor Bernd Wiesberger. "It's nice to be able to take it out and bring it out here".
THE Abu Dhabi HSBC Championship boasted one of the strongest fields on the European Tour previous year, and this week's renewal will be even stronger. I started hitting balls just before Christmas.
The youngster and the world number one played at the Abu Dhabi Golf Club and the American Ryder Cup star was impressed by the Dubai-based youngster.
Both Norris and Paratore hit nine birdies, but bogeyed the par-three seventh.
Paratore, 23, is bidding for his second European Tour title after being beaten in a play-off at the Mauritius Open last month. Anybody who plays this game knows that a lot of it is built on confidence, a lot of form is built on confidence and that's what I gained from here a year ago.
"Considering how far I'm hitting, I don't think that will be an issue anymore".
"It gave me confidence for the rest of the day, and I kept making putts, so it's been a really good day".
"Hopefully his body holds up because it's good for the game, it's good for golf, it's good for everybody", Koepka said to Omnisport after being asked about Woods' prospects for this year and beyond.
World number one Brooks Koepka is tied third at the Abu Dhabi Championship after his first competitive round of golf in three months following injury.