Lahiri finished tied 46th at the Wyndham Championship on Sunday to earn the 121st spot on the FedEx Cup standings, which ensured his playing rights for the 2021-22 season, beginning in September.
The 33-year-old Indian, who has now been on the PGA Tour since 2016, has yet to make his breakthrough and has now hit a rough patch in 2021.
PGA Tour Championship: World No 1 Dustin Johnson claims three-shot victory to clinch FedEx Cup, $15 million prize
Dustin Johnson became the first No 1 seed at the Tour Championship to win the FedEx Cup since Tiger Woods in 2009.
Dustin Johnson's manager said in a text message on Monday that the FedEx Cup playoffs hold as much importance to Johnson as chasing a gold medal in Tokyo this summer.
The five-time major winner Phil Mickelson said he had to leave his clubs and clothes behind when his hotel was evacuated.
Tour Championship: Tiger Woods wins first PGA Tour title in five years to cap off incredible return to golf
Tiger Woods, in his Sunday red shirt, both arms raised in victory on the 18th green. For so many years, the scene was familiar. This time, it was surreal.
FedEx Cup: Tiger Woods shares lead with Justin Rose in Tour Championship at halfway stage; Rory McIlroy still in contention
Tiger Woods edged closer to snapping a five-year winless drought as the 14-time major winner maintained a share of the lead on Friday at the halfway stage of the Tour Championship.
FedEx Cup: Tiger Woods returns to PGA Tour Championship with share of lead; Justin Rose grabs advantage
Woods already considers this a successful year just by making into the 30-man field at East Lake for the FedEx Cup finale, where everyone has a mathematical shot at capturing the $10 million bonus.
The 22-year-old Spieth became golf's first $22 million man — a PGA Tour record with just over $12 million in prize money, and the $10 million bonus for the FedEx Cup.
On a day when six players had at least a share of the lead, Mahan found a way to make it look like a comfortable win.
Even with a four-shot lead, the final round was a battle. There were two trophies on display on the first tee. He knew he could still win the FedEx Cup even if he didn't win the Tour Championship. He figured good golf would take care of everything, and it did.
Johnson rolled in two birdie putts over the closing holes at soggy Conway Farms and closed with a 6-under 65 for a two-shot victory over Nick Watney.
The Northern Irish world number four, winner here last year during a storming finish to his 2012 campaign, battled to a six-over-par 77 to end the second round at Conway Farms Golf Club stone last in the elite field of 70.
The 37-year-old Swede moved to the top of the FedEx Cup standings after two playoff events, assuring him his first trip to the Tour Championship and a clear shot at the $10 million prize.