There's an old joke where Bob is taking care of Jack's house while Jack is out of town, and Jack's cat dies.
Bob wants to break it to him gently, so the first time Jack calls to check in, Bob just tells him "Oh, your cat is on the roof and I can't get him down.." Then the next time he says "oh boy, you know your cat is still on the roof, and I'm not hearing any noises so I'm getting worried." Then at the end of the week he finally tells Jack the bad news.
Jack is distraught, but tries to keep himself together and asks "how is grandma doing, is she taking it okay?" Bob pauses, and says "Oh, uh, Grandma is on the roof and I can't get her down." [rimshot]
Seems to me this here is Barry Bonds' way of saying "my drugs are on the roof and I can't get them down." At this point he knows he'll have to fess up soon, but he's trying to ease his way into it.
