ESPN's "Man in the Arena," a documentary-series about the early and current playing days of quarterback Tom Brady, has been a hit since its debut a few weeks ago.Each week it seems that fans are treated to another unknown aspect of the seven-time Super Bowl winner. Brady has shared stories from his rookie season and beyond in each week's episode. Each episode of the series also features interviews with Brady as well as former teammates who also reflect on the experiences that they have had while playing the game.But it seems one former teammate wasn't asked to be a part of the "Man in the Arena" documentary and made it known in a post on social media.Former New England Patriots backup quarterback Matt Cassel tweeted that he wasn't asked to be a part of the series and he suspects his invitation was lost in the mail.But it was the tweeted reply from Tom Brady that has everyone laughing about the exchange between the two former teammates.Also Read: How did Tom Brady react to Bruce Arians calling Bucs 'Dumb football team'?Tom Brady has a funny comeback for former teammate Matt CasselCincinnati Bengals v Kansas City ChiefsMatt Cassel spent four seasons with the New England Patriots, including taking over as starter when Tom Brady tore his ACL in 2008.Cassel was watching Tom Brady's "Man in the Arena" documentary series from home and on his television and was not a part of the series as other former teammates were.Cassel tweeted and tagged Tom Brady saying that he believes his invitation to be included in the interview was 'lost in the mail.' Brady responded that Cassel was on speed dial in case Bernard Pollard showed up at the studio.Tom Brady@TomBradyWe had Matt on speed dial in case Bernard Pollard showed up at the studio twitter.com/m_cassel16/sta…Matt Cassel@M_Cassel16Yo @TomBrady, I think my interview invite for Man in the Arena got lost in the mail.12:53 PM · Dec 15, 20213000231Yo @TomBrady, I think my interview invite for Man in the Arena got lost in the mail.We had Matt on speed dial in case Bernard Pollard showed up at the studio twitter.com/m_cassel16/sta…Brady was referencing the tackle from Pollard that caused Brady's season-ending knee injury in the first game of the 2008 NFL season. That led to Matt Cassel taking over as the starting quarterback for the New England Patriots for the rest of the season.Pat McAfee@PatMcAfeeShowMan in the Arena has been an AWESOME look at what makes @TomBrady great #PatMcAfeeShowLIVE2:04 AM · Dec 15, 2021615Man in the Arena has been an AWESOME look at what makes @TomBrady great #PatMcAfeeShowLIVE https://t.co/3RlfDqFwhTBrady's poking fun at his own injury and the fact that Cassel had to be on standby just in case he couldn't finish out the series is what caught a lot of fans by surprise and caused a lot of laughs on Wednesday afternoon.Also Read: Watch: NBC uses Adele's "Hello" in promo for Tom Brady's first game against Patriots