(CNN) PGA Tour commissioner Jay Monahan called the launch of the controversial LIV Golf series an "unfortunate week that was created by some unfortunate decisions."
Speaking at the Canadian Open on Sunday, Monahan made his first public appearance since banning 17 players for participating in the Saudi-backed LIV Golf series, which teed off on Thursday.
He said the PGA Tour's decision to ban the players participating in the new series, which includes major winners Phil Mickelson and Dustin Johnson, was due to a violation of tournament regulations.
"It's my job to protect, defend and celebrate our loyal PGA Tour members, our partners and our fans, and that's exactly what I did," Monahan, who was speaking on CBS, added.
The LIV Golf series is backed by Saudi Arabia's Public Investment Fund (PIF) -- a sovereign wealth fund chaired by Mohammed bin Salman, the Crown Prince of Saudi Arabia.
The PIF has pledged to award $250 million in total prize money to the series. Each of the first seven events will have a total prize purse of $25 million, with $20 million split between individual players and the remaining $5 million shared between the top three teams at the end of each week.
Charl Schwartzel, the winner of last week's individual stroke-play competition at the inaugural LIV Golf event in London, earned $4 million as he finished one stroke ahead of Hennie du Plessis.
Schwartzel's four-man team, Stinger GC, also won the team competition by 14 shots over Crushers GC and will split the $3 million prize.
Asked why players are not allowed to play in the PGA Tour and the LIV Golf series, Monahan said: "Those players have chosen to sign multi-year, lucrative contracts to play in a series of exhibition matches against the same players over and over again. You look at that versus what we see here today and that's why they need us so badly.
"You've got true, pure competition -- the best players in the world here at the RBC Canadian Open with millions of fans watching.
"In this game, it's true and pure competition that creates the profile and the presence of the world's greatest players. And that's why they need us, that's what we do.
"But we're not going to allow players to free-ride off of our loyal members -- the best players in the world."
Rory McIlroy, who previously said he "can't see any reason" why anyone would join a breakaway league when news of the venture first emerged, successfully defended his title at last weekend's Canadian Open, finishing two strokes ahead of Tony Finau and four ahead of Justin Thomas.
Monahan was also asked by Jim Nantz how much of an issue it was that the money funding the LIV Golf series was coming from Saudi Arabia, to which he replied: "Well, it's not an issue for me because I don't work for the Saudi Arabian government. But it probably is an issue for players that chose to go and take that money.
"I think you have to ask yourself the question, Jim, 'Why?' Why is this group spending so much money, billions of dollars, recruiting players and chasing a concept with no possibility of a return? At the same time, there's been a lot of questions, a lot of comments about growth of the game and I ask, 'How is this good for the game that we love?'"
On Friday, a coalition of families and survivors of 9/11 sent an open letter to several players competing in the LIV Golf series, which they called a "sports washing" campaign by the Saudi Arabian government.
When asked about the letter, Monahan said: "As it relates to the families of 9/11, I have two families that are close to me that lost loved ones. And so my heart goes out to them.
"I would ask any player that has left or any player that would ever consider leaving, 'Have you ever had to apologize for being a member of the PGA Tour?'"