Board Thread:General Discussion/@comment-5398287-20130625202043/@comment-1387259-20140515123915

Kyūkyoku KON wrote: There's a bit of a difference between the online translations and the Viz translation in volume 60 concerning this. The online version has Kensei telling Hisagi he'll probably die if he doesn't RELEASE his bankai, while the official English translation by Viz has Kensei saying he thinks he'll need to ACQUIRE bankai if he doesn't want to die. That's enough to cast doubt in my mind.

I saw a Viz copy of 60 myself and that is indeed what it says. Now I just dug up cnet's version (here)

Kensei: Watch yourself, Shuuhei. Mashiro's Hollow form is pretty damn strong. / I'm pretty sure achieving Bankai is your only chance if you want to survive. Hisagi: H... Hold on, Kuna! // Captain Muguruma! / This is far too sudden, I -

Given that the one of the most trusted sources here implies he was (unwillingly) training to achieve Bankai, I'm going with he didn't have it. Now whether or not he actually got it from that drilling session we don't know, but that's not important at the moment.