Jack's problem is not knowing when to stop.
Can be good as gold for months on end but then if there's a party he's on it more than anyone. So he's not drinking all the time, but when he is drinking he makes up for that.
Far from ideal but if he's lucky he'll be able to keep his fitness during the season by keeping his binges to the off-season.
So far he's been very lucky as outside of the negative headlines his drinking hasn't really impacted him. Not unreasonable to think it might become more of an issue as he gets older. Also considering his kidney getting fucked up a few years back, got to assume drinking isn't a great idea to avoid that becoming a problem.