Former Eli Manning's teammate Antonio Pierce shares his perspective on why he doesn't think Manning did anything wrong with his game-worn memorabilia. (1:42)

A memorabilia dealer who is involved in the lawsuit alleging that the New York Giants and quarterback Eli Manning were complicit in passing off fake game-used memorabilia took to social media to explain where his company currently stands.

Brandon Steiner of Steiner Sports appeared on Facebook Live on Monday afternoon to say he's hoping the items Manning gave to him and presented as game-used, that he then sold, were legitimate, but he isn't sure at this time.

"When Eli Manning walks into your office and he says, 'These are my game-used items,' then I'd like to think that I can believe that," Steiner said.

Last week, an attorney for the plaintiffs -- collectors Eric Inselberg, Michael Jakab and Sean Godown -- introduced an email sent by Manning on April 27, 2010, to Giants equipment manager Joe Skiba, in which Manning asked for "two helmets that can pass as game-used" for his Steiner memorabilia deal.

Steiner said Monday his company has had a deal with Manning since his 2003 rookie season and that for a period of about five years, Manning threw in two to three game-used items per season as part of a bonus to his contract.

"It's probably why it was a bit of an afterthought for Eli to get us those items when you read some of those emails," Steiner told the audience watching him at his desk on Monday.

Steiner later told ESPN he was out of the country when the story broke and had not yet had a chance to speak to Manning.

"The email, taken out of context, was shared with the media by an unscrupulous memorabilia dealer and his counsel who for years has been seeking to leverage a big payday," McCarter & English, the law firm representing the Giants in the case, said in a statement issued last week. "The email predates any litigation, and there was no legal obligation to store it on the Giants server. Eli Manning is well-known for his integrity, and this is just the latest misguided attempt to defame his character."

"When Eli Manning walks into your office and he says, 'These are my game-used items,' then I'd like to think that I can believe that," Steiner Sports CEO Brandon Steiner said of the items the Giants QB, above, offered up to him as game-used. Matthew Emmons/USA TODAY Sports

When asked by a viewer why he didn't sever his deal with the Giants quarterback, Steiner said he firmly was giving Manning the benefit of the doubt but still didn't have the answers.

"First of all, we haven't gotten all the facts and we don't know if Eli has done anything wrong," Steiner said. "Secondly, I think we are all better than our worst mistake. We've had a 14-year relationship with a guy that's amazing to us. He has been a great partner, he has been a friend and he has been amazing to our customers in every sense of the word. I'm not a runner -- you've seen me with Ray Rice, you've seen me with a lot of other players, guys that have been with us. We're going to do everything we can to support those players when the waters get a little rocky."

Steiner had yet to research what ultimately became of the helmets that Manning presented him and to whom, if anyone, the helmets were sold. Steiner said that prior to any conclusive findings, anyone who bought one of the dozen or so game-used Manning items from him over the years could get a complete refund now.

"This is troublesome to me," Steiner said. "Yes, I lose sleep because I see this. There's an accusation out there that something we thought was 100 percent real was in question."

Steiner admits that the chain of custody isn't perfect with game-used items.

"A lot of times, we're not in the locker room, and there are a lot of leagues and teams that don't have authentication programs that really secure product," he said.

One of the methods Steiner has used for authentication is matching what is received with photos from the game, though the lawsuit alleges that the Giants' equipment manager is very aware of markings on jerseys and helmets.

A trial in Bergen County (New Jersey) Superior Court is scheduled to begin on Sept. 25.