SCOTTSDALE, Ariz. -- Major League Baseball commissioner Rob Manfred apologized Tuesday for describing the World Series trophy as "a piece of metal" during an on-camera interview with ESPN, a description that drew pointed criticism from Los Angeles Dodgers third baseman Justin Turner and Chicago Cubs starting pitcher Jon Lester.

Manfred said he referred to the World Series trophy, named the Commissioner's Trophy, "in a disrespectful way" while attempting to make "a rhetorical point" about the possibility of stripping the Houston Astros of their 2017 championship.

"I want to apologize for that," Manfred said at a news conference at the Omni Scottsdale Resort. "There's no excuse for it. I made a mistake. I was trying to make a point, but I should've made it in a more effective way, and again, I want to apologize for it.

"I will say this: I've awarded five World Series trophies. There is no greater pleasure in this job than awarding that trophy. I understand what it means, and again, it was a mistake to say what I said."

Manfred spoke two days after he addressed a media contingent in Florida in another news conference that appeared to make fans and players angrier with his handling of the Astros' sign-stealing scandal.

On Tuesday, Manfred again defended the investigation and punishment. He addressed assertions from players that MLB chose not to respond to an assortment of sign-stealing concerns that were filed to the league over the years by saying that "every complaint about sign stealing, whether it involved the Houston Astros or another club, was investigated by our office in real time at the time that complaint was made."

Manfred acknowledged that he could have set precedent by stripping the Astros of their title, but he said he would be "very concerned about opening the door to altering results that took place on the field."

"There are a lot of things that happened in the history of the game that arguably could be corrected," Manfred said, "and I just think it's an impossible task for an institution to undertake."

In its investigation, the league found that the 2017 Astros used a live feed from a center-field camera to decipher the opposing catchers' signs in real time and deployed a system that involved banging on a trash can to alert their hitters of upcoming pitches, supporting comments made by Mike Fiers to The Athletic in November.

Astros general manager Jeff Luhnow and manager AJ Hinch were suspended by Manfred for the 2020 season and subsequently fired by team owner Jim Crane. The team was fined $5 million, the maximum amount, and lost a total of four draft picks within the first two rounds in 2020 and 2021.

Many, both inside and outside the game, have taken issue with the fact that Crane wasn't directly punished and that the players were granted immunity for their testimony.

Manfred reiterated that Crane was unaware of the Astros' sign-stealing practices and noted that the owner was nonetheless affected by the punishments levied against his team. Manfred also said the Major League Baseball Players Association did not allow the league to interrogate players without granting them immunity.

"We would not have gotten where we got, in terms of understanding the facts, learning the facts, disclosing the facts," Manfred said, "if we hadn't reached that agreement."

In a statement later Tuesday night, the MLBPA confirmed that, in the wake of The Athletic story, it sought confirmation from the league that players connected to the allegations would not be disciplined. The union said it received that confirmation promptly, and player interviews in the league investigation began soon thereafter.

"Any suggestion that the Association failed to cooperate with the Commissioner's investigation, obstructed the investigation or otherwise took positions which led to a stalemate in the investigation is completely untrue," the union said as part of its statement. "We acted to protect the rights of our members, as is our obligation under the law."

Manfred said he will uphold his promise of immunity for Astros players but admitted that he might have to "think long and hard" about granting immunity again in the future. The union, in its statement, said it has exchanged proposals with the league in recent weeks on potential rule changes for affecting sign stealing and other areas, and "we have made it clear to MLB that no issue is off the table, including player discipline."

The commissioner said he recently met with managers from the 29 other teams to emphasize that pitchers should not take justice into their own hands by intentionally throwing at Astros hitters, an issue that was raised by new Houston manager Dusty Baker. Manfred also promised to "take every possible step" to protect Fiers, who currently pitches for the Oakland Athletics.

"I want to be really clear about this: Mike, who I do not know at all, did the industry a service," Manfred said. "I do believe that we will be a better institution when we emerge at the end of this episode, and without a Mike Fiers, we probably would have had a very difficult time cleaning this up. It would have taken longer. I think we would have done it eventually, but it would have taken a lot longer, and I have a real problem with anyone that suggests Mike did anything other than the right thing."

Manfred said he believes the league needs to "drastically restrict in-game access by player personnel to video" in an effort to curb sign-stealing practices, but MLB and the MLBPA are still working through new protocols.

Manfred, entering his sixth season as commissioner, is in the thick of a particularly turbulent time in his sport. Revelations about an uneven playing field have increased cynicism from players and triggered mistrust from fans. Players are openly criticizing the commissioner and their peers in ways that seem unprecedented. A game that is bursting with young talent is marred by a cheating scandal that has shown no signs of losing momentum.

"I think that trust is something that has to be earned -- or earned back," Manfred said. "I think that we have tried to send our fans the message that no matter who's involved, if there is an allegation that involves a violation of the rules, we'll investigate it. We'll investigate it with tremendous vigor and effort. We did that in Houston. We're doing it again in Boston.

"I think we need to show our fans that not only have we taken steps to prevent this type of activity, but we continue to take steps to ensure fans that it's not going on on a go-forward basis. And I have to say, that's a joint obligation. It's something we have to do, and it's something that the players have to help us do."