Here's Allen Barra from today's Salon.
There is only one player in the PED era who unequivocally got a boost from whatever he took: Barry Bonds. Bonds was a better player from age 35 through 40 than he was from age 25 through 30. I can’t think of another player in baseball, in fact, another professional athlete about whom this can be said.
I do not have an encyclopedic level of understanding of the statistical swings of every player in baseball history, but I've looked at my share of baseball-reference pages. Here's Jose Cruz. The father, not the son who dropped the fly ball in the NLDS against the Fish.
In 1982 Jose Cruz was 34 - here was his slashline: .275/.342/.377. His OPS+ was 109, his WAR was 2.3
That made sense. Cruz was clearly in his decline phase. His OPS+ in '79 was 121, the next year 127, then 115. His WAR in those years similarly declined; and then, in '82, at the age of 34, Cruz had his lowest OPS+ since 1973 and lowest WAR since '74.
Here was 35 year old Jose Cruz in 1983: .318/.385/.463 OPS+ 142 WAR 6.2
He led the league in hits.
He stole 30 bases.
And then here was 36 year old Jose Cruz in 1984: .312/.381/.462 OPS+ 145 WAR 6.3
The two best seasons in Jose Cruz's life came when he was 35 and 36 years old.
I have no idea if Jose Cruz took PEDs.
Let me ask you this - how old was Hank Aaron in his best season with the bat?
He was 37. When Hank Aaron was 37 his OPS+ was 194, the high mark of his career, the high mark in baseball that season (he also led baseball in slugging%).
I have no idea if Hank Aaron took PEDs.
I assume Barry Bonds did; I assume they were of benefit - but even in a piece like Barra's, which largely runs against the prevailing wisdom of PEDs as magic pills, he still takes the posture that Bonds's late career spike is without precedent - but you can find counter-examples. An 8 WAR season is an MVP caliber season; Bonds hit 8 WAR for the first time when he was 24 years old in 1989, and except for the strike season of '94 and an injury shortened season in '99; Bonds never had a season lower than 7.5 until he was 40 years old. Bonds killed it every single season. He was Babe Ruth.
You could have thrown an MVP vote at Barry Bonds in every season from '89-'04 except for one year.
That's the career Barry Bonds had.