Paulie Malignaggi throwing in towel as Conor McGregor sparring partner

Malignaggi fed up with McGregor circus (1:33)

ESPN's Brett Okamoto explains what led to Paulie Malignaggi quitting as Conor McGregor's sparring partner. (1:33)

LAS VEGAS -- Retired boxer Paulie Malignaggi, hired to be a sparring partner for UFC star Conor McGregor, told ESPN he won't continue and likely will fly home after photos surfaced Thursday appearing to show McGregor in a favorable light during Tuesday's 12-round session.

McGregor, who is scheduled to face Floyd Mayweather (49-0, 26 KOs) in the boxing ring Aug. 26 at T-Mobile Arena, had twice used Malignaggi, a former two-weight world champion, as a sparring partner.

"I wanted to be part of this event, but I didn't want to become the story, and that's what this has turned into," Malignaggi told ESPN by phone Thursday night. "I won't release any information about his game plan or what he's working on; I wouldn't do that. But this has become a fiasco. It's a circus.

"And I do want that sparring video released. The UFC's PI definitely has that video. I understand it can't come out now, but Conor, if you have any balls, release what really happened."

On Wednesday, Malignaggi described Tuesday's session as having "a lot of violence." He said he went into the session with a chip on his shoulder because McGregor invited a small audience to watch.

Since then, photos of the session have emerged online, showing McGregor favorably. The Irish star's personal photographer posted a shot of him landing a left uppercut.

Another shot by McGregor photographer Dave Fogarty shows Malignaggi falling backward on the canvas as McGregor stands over him. Malignaggi said the knockdown was actually a "pushdown."

Earlier Thursday, Malignaggi challenged McGregor to release unedited footage of the entire contest.

In a statement issued later Thursday, Malignaggi emphasized that he believes he and McGregor have "a mutual respect inside the ring" and that his decision was based on issues he disagreed with outside the ring.

"It's not my place to dictate terms in a training camp that is not mine, but it's my place to decide if I want to be a part of it," Malignaggi said in the statement.

Malignaggi, who retired from professional boxing earlier this year, told ESPN on Wednesday there were zero knockdowns during the session but said McGregor had shoved him to the canvas at one point.

"There was a pushdown yesterday," Malignaggi said of the sparring session. "Conor on the inside, he can get a little rough. He shoved me down, you know, but no knockdowns. Obviously, 12 rounds, you're gonna see there's a mark on my face. Very, very hard work for both of us. I was starting to get in a groove in the middle rounds, starting to land some good shots. Conor really came on strong in the end. It was back and forth."

Malignaggi also characterized his relationship with McGregor as being like "frenemies."

Tiernan Bradley, another McGregor sparring partner, confirmed Malignaggi's descriptions of "violence" to the Irish News earlier in the week, saying, "Conor told us all when Paulie came into camp, 'This is not a spar. I want to fight him. I'm ready for a war.'"

Veteran referee Joe Cortez, who has been hired to officiate the sparring sessions, has also commented on the back and forth, saying he has been forced to step in on several occasions to bring the fighters under control.

McGregor, 29, is a two-weight UFC champion and the current lightweight titleholder. This month's lucrative fight against Mayweather will mark his professional boxing debut.