TAMPA, Fla. -- Major League Baseball commissioner Rob Manfred told reporters Thursday that this will be his final term in office and he will retire when it expires in January 2029.

Manfred, 65, replaced Bud Selig as commissioner in January 2015 and has since been given two five-year terms. The owners voted in July to give him a third term.

"You can only have so much fun in one lifetime," Manfred said to reporters at Grapefruit League media day in Tampa, Florida. "I have been open with [owners] about the fact that this is going to be my last term."

Manfred, a lawyer who has worked with MLB since 1987 -- first as outside counsel, then as a chief negotiator for labor matters -- took over from Selig, who spent 18 years as commissioner.

In Manfred's tenure, the game has undergone vast changes. The successful implementation of a pitch clock last year coincided with a nearly 10% increase in attendance, and in 2022, Manfred oversaw playoff expansion to 12 teams.

His tenure will in part be defined by his handling of the Houston Astros' cheating scandal, in which he gave players blanket immunity in exchange for their testimony. "Maybe not my best decision ever," he told Time.

Manfred also oversaw the lockout of players in 2021-22 that pushed the game to the precipice of a significant work stoppage. The league and the MLB Players Association eventually struck a deal on a five-year collective bargaining agreement that will expire after the 2026 season.

Before Manfred leaves the job, he said Thursday, he hopes to have a process "in place" for the league to expand to 32 teams.

Manfred preaches patience on new uniforms

Although some players -- and many fans on social media -- have criticized the new Nike Vapor Premier uniforms for looking like cheaper replica jerseys, Manfred said they will become "popular" with time.

"We always pay attention to what people are saying about any new initiative. As you know in baseball, with any new initiative there's going to be some negative feedback," Manfred said. "First and most important, these are Nike jerseys. We entered into this partnership with Nike because of who they are and the kinds of products they produce."

There have been multiple reports about players not liking the look or fit, however. Players have also complained there are fewer tailored options available for the pants.

One player, who wished to remain anonymous, told ESPN.com: "They're not great, definitely not an advancement."

"The jerseys are different," Manfred said. "They're designed to be performance wear as opposed to what's been traditionally worn, so they are going to be different. But they have been tested more extensively than any jersey in any sport. The feedback from the All-Star Game last year where the jerseys were worn was uniformly positive from the players, so I think after people wear them a little bit, they're going to be really popular."

Owners push for free agent signing period

With several top free agents still unsigned, including National League Cy Young winner Blake Snell and postseason hero Jordan Montgomery, Manfred said the owners would prefer a free agent signing period similar to other sports in order to expediate the process.

"We actually made proposals to that effect to the MLBPA. They were not warmly received," he said. "With the system we have right now, one of the tactics that's available to player representatives is to stretch out the negotiation in the belief they're going to get a better deal. That's part of the system right now. There's not a lot we can do about it. Certainly, from an aspirational perspective, we'd rather have two weeks of flurried activity in December, preferably around the winter meetings where you're all there to write about it."

Manfred 'confident' on A's move to Vegas

There were no new updates on the Oakland Athletics' move to Las Vegas or the pending sale of the Baltimore Orioles to private equity billionaire David Rubenstein. Manfred said that he remains "confident" that the move to Las Vegas is "solid" and that the league hopes to move quickly in approving the Orioles' sale.

While the A's will play in Oakland in 2024, they are still searching for a temporary home until the proposed Vegas stadium would open in 2028. With the 2025 schedule finalized in July, Manfred said the A's will need to settle on the 2025 home before then.

MLB to support teams in DSG fallout

The fallout from the Diamond Sports Group bankruptcy case is still ongoing, but Manfred reiterated that the league would be prepared to back teams.

"Any club that Diamond walks away from, we will be in a position to support them, both in the traditional cable model and the digital side of the house," Manfred said. "It doesn't matter whether it's three more or 10 more, we will handle them."

MLB took over the local broadcasts for the San Diego Padres and Arizona Diamondbacks last season after Diamond walked away from those deals.

Following up on teams fabricating injuries

Manfred said the league is still looking into teams fabricating player injuries, an issue for which he suspended former New York Mets general manager Billy Eppler last week.

"I've read a couple comments from players that we're following up on," he said. "If in fact it is more widespread, it concerns me, because it's a form of cheating and it's incumbent upon us to figure out if it's more widespread. One thing I've been absolutely clear about: The fact that you allege that somebody else is doing is not a defense if we catch you. Everyone has their own personal responsibility on these issues."

ESPN's Jeff Passan contributed to this report.