Has to be within a reasonable timeframe, so fighters retiring and then coming back several years later don't count.
(granted the prime-corroding decline began with the beating from Tito and was exacerbated by the one from Golden Boy - except it manifested gradually and didn't fully avalanche into a steep vertical drop until between the meetings with Shane)
Yeah, Vargas looked like he had rigor mortis in their second fight. His legs were so stiff and he wasn't able to keep his balance after throwing shots.
Erik Morales from Pacquiao II to III. I don't agree with the premise that he was entirely washed up in the second fight (the early rounds looked far too much like the first fight for that to be the case) but he was CLEARLY not the same guy in the third fight.
Morales is a WEIRD case. He looked shot to **** in Pac III but - turns out he wasn't. Or at least he caught a career second wind and was somehow hanging with ranked guys like twice his size well past his sell-by.
Morales from Pacquiao II to III is a really good shout, as well. Again, it seems like one of the telltale indicators of a steep decline are shaky legs. I think I recall Steward even mentioning how weak and uncoordinated Morales looked on his feet in the first round or two. Hopkins doesn't count post-Kovalev because he took over two years off, but in the opening round against Smith, you could tell he was shot to pieces by looking at the lack of bounce and the rigidity in his movement. You got the feeling with guys at this stage that some hard shots will cause them to crumble.
I wonder if his mini-resurgence (if you could call it that) at 140 was not having to cut so much weight?
Almost definitely a factor, yeah. But a big part of the game is mental, and in the Pacquiao rubber match he looked a man who didn't want to fight...or rather, like a monk who didn't even want to slap a fly. And later, fire was back roaring with the fury of a thousand suns.
Don't know if others agree, but I thought I saw a noticeable decline in Kovalev from the Alvarez rematch to Yarde. In IB's RBR, I remember posting early in the fight that Kovalev looked pretty washed-up by his standards.
