Floyd Mayweather thinks Kell Brook is in for a "rough" ride against Errol Spence Jr - and thinks the fight will not go the distance.
IBF welterweight champion Brook takes on mandatory challenger Spence Jr at Bramall Lane, Sheffield, on May 27.
It will be Brook's first fight since stepping up to middleweight and being stopped by Gennady Golovkin in September.
Brook sustained a broken eye socket in that fight and although he is sparring without any recurring problems, Mayweather thinks he might suffer when he goes in with Spence Jr.
"I think him and Kell Brook is a good match-up but I don't think it's going the distance," he said.
"I think Brook took a lot and it was a tough fight between him and Triple G, so I think, coming on the back of that, it's going to be a tough fight.
"It's not really fast but hopping into another tough fight like that, right after the Triple G fight? It's going to be rough."
Brook had started his preparation out in Tenerife but is now back at the Wincobank and has been sparring with unbeaten light-heavyweight Amer Khan.
