yes, you can. i've done it 2 times in the past, both resulting in acetylaldehyde, even after a 4 week primary with 1 week at diacetyl rest temps.
both because I observed the viability factor on Mr. Malty and pitched almost 1500mL of loose slurry in 10gal.
I was able to rescue the beers by letting them sit at room temp (acetylaldehyde has a low boiling point - like 60s or 70s) and bubbling Co2 periodically from the bottom to degas the kegs, thanks to some advice from posters here.
As for your situation - 230mL is a little more than a cup - I would pitch a cup and a half and you will be in the ballpark and be fine.