Last night, 'Glee' aired 'The Quarterback,' its long-awaited tribute to Cory Monteith. It was both a beautiful testament to Monteith himself, and his character, Finn. One crucial character did not appear in the episode, however: Dianna Agron, who played Finn's girlfriend, Quinn, on the series.

She had not been invited to do the tribute episode with the rest of the cast. And now reports are claiming that Agron's exclusion is due to 'Glee' co-creator Ryan Murphy and Lea Michele's dislike of the actress.

According to the RadarOnline, a FOX insider claims that Murphy and Michele, Monteith's longtime girlfriend and 'Glee' co-star, "intensely dislike Dianna and have both worked to marginalize her as much as possible."

"They never saw her as a team player," added the source, who also pointed out that although Agron is not contracted for Season 5, other non-contracted actors returned for the memorial episode, "even ones with less of a story connection to Finn than Dianna had," the insider claimed.

However, a different source has shot down these rumors, telling E! Online that reports of bad blood between Agron and her co-stars are "not true at all."

"She is still very much a part of the 'Glee' family and always welcome," the E! source revealed.

One telling sign that things are amicable between the 'Glee' co-stars: Agron attended a private memorial service for Monteith, which was held on the Paramount Studios lot where the show is filmed.

And Agron herself has spoken openly about remembering her friend, telling Katie Couric:

“We all have … nothing but the truth, which is that he was one of the most amazing people that I’ve ever met," she said. "Generous, loving, kind and that’s how he’ll always be remembered.”