Welterweight Brook, who takes on the Argentinian at the Sheffield Arena, was given a rough ride in his last bout against dogged US pugilist Carson Jones before he eventually prevailed, bloodied and with his nose broken, via a majority points decision.
That wake-up call prompted Brook to intensify his training this time round, with a crack at the IBF welterweight title — which will be held by either Devon Alexander or Randall Bailey — on the line.
“I’m in the best shape I have ever been in. It’s the best I have ever felt and the easiest I have made the weight. I’m feeling strong and I can’t wait for Saturday night,” he said.
Brook had always thought himself in top condition, but his struggles against Saldivia have made him work harder than ever.
He said: “It’s a big eye-opener, you never stop learning and I have taken my body to places it’s never been before. It’s been crying in pain, not wanting to be there but it’s had to go there because that’s what I have been told to do.
"I’m now benefiting from the recovery, my heart rate is back down and everything is superb.”
Standing between Brook and a world title shot is 28-year-old Saldivia, who has an impressive record of 41(32)-2.
“He’s no easy pickings,” said Brook. “He’s earned his right to be ranked where he is, he’s no walkover and is going to be very tough.”