Oh, this is bad news:
It was announced that Jeffress tested positive for a "drug of abuse." The specific drug was not identified by baseball but I've been told by people familiar with the situation that Jeffress has been caught using marijuana more than once.
The club-administered test that Jeffress failed during the fall instructional league program in Arizona does not fall under the auspices of the minor league drug program. Thus, it's up to the club to apply any disciplinary measures it feels is appropriate.
I generally try to keep my political/social views far from this blog, but this is just plain stupid. If marijuana is why Jeffress was suspended in the first place, that's ridiculous. There's no good reason for pot to be illegal, and organizations and employers (such as MLB and the Brewers) shouldn't be intruding in this aspect of their players' lives unless the drug use is interfering with their performance.
On the flip side, though, Jeffress is pretty stupid, too. The rules are well known to players, and Jeffress's future is really, really bright for him to (literally?) piss away just to toke up now and then. It's not fair, but it's a pretty easy rule to follow if you care about making it in baseball.