EF 100-400mm f/4.5-5.6 L IS USM suitable for pro wrestling in a stadium?

[theperfectplex]

Was thinking of grabbing the Canon EF 100-400mm f/4.5-5.6 L IS USM used to go on my R6. I recently shot a live tv wrestling show with a Tamron 70-200mm from the media/hard cam seats in a arena and it was perfect. Looks like ill be getting a chance to shoot a much bigger event in a football stadium from a media area behind the crowd or a press box. Ill need some extra reach but a 2.8 price is way out of my price range. The ring will be very will lit on the 50 yard line but it'll run into twilight and nighttime. Would the 4.5 not be fast enough? Itll be on an R6. I don't mind bumping the ISO but I wanted to try and edit as little as needed. 

[rs-eos]

Will this be a one-time event? If so, consider renting a relevant f/2.8 lens.

[theperfectplex]

1 for now. But potential for more. 

[ebiggs1]

"...  from a media area behind the crowd or a press box."

Impossible to answer without knowing the actual distance.  I did a lot of shooting from the sound booth in our auditorium and I used my Sigma 150-600mm f/5-6.3 DG DN OS Sports Lens and Sigma 120-300mm f/2.8 DG OS HSM Sports Lens. You can judge the distance as normal auditorium size. I never measured the distance.

At 100mm, I got pretty good sized stage area view. At 600mm I could get half body portraits. My gut would tell me 400mm will be on the short side but again without knowing the actual distance who knows. I know that because I started out with the EF 100-400mm and found the FL too be too short.