Right now he is not. He is pushing 40 and unless he finishes extremely strong I will have to pass.
His candidacy is not a total joke as he won a Cy Young and also finished 2nd and 3rd in the voting in other years. In addition, he was the ace on some Cardinal teams that won the World Series and I don't know if there was a pitcher I'd have rather had pitching for my team in the postseason last year.
However, if he retired today I don't think it's enough.