I just cut him earlier today. Herniated disks just don't heal very quickly. Actually, they are very slow to respond. I think he may be back by the all-star break, and even then he's just one wrong move from going back on the DL. Bad backs almost never fully heal. I'd dump him unless you have unlimited DL slots or enough DL slots that it doesn't matter how long he's out. Me, only 1 DL slot and with our daily league all bench players get used at some point during the week. I already have Nelson Cruz, Brett Anderson, and De La Rosa on the DL. I had to dump Roberts and De La Rosa (who may be back in about 10 weeks if he's lucky) as I can only afford to eat 1 zero on my bench (Cruz- who's hopefully back in another 8 days or so). Anderson gets the one DL spot. Bye-bye Brady, I'm going to miss you. I've had him each of the last 3 years that I've played and he has been great for me. Just not this year.
Keep him if you have enough DL spots, otherwise dump him.