Jose Canseco, the 'fraidy cat?

OK, I'm confused. Jose Canseo publishes a book about he and half the known baseball world were loading up on steroids and how steroids in fact can be good for your athletic career (he says this, of course, before his liver falls out and his gonads shrink). But when the Senate subpoenas him to show up and discuss his past exploits with the juice on the record, he asks for immunity? Maybe his gonads are shrinking - or maybe he's just getting sound legal advice before he presents himself to the federal government. No, I like the first theory better - it's sexier, for some reason.