Burke has been offered to me in trade so I've really been studying up on his playing time prospects this year.
It doesn't look good. I don't see how he will get any more at bats than last year, and in fact it looks worse. The Astros are semi-actively looking on the free agent market for a LFer including having an offer in to Nomar. Other vets like Rondell White are also being considered.
So even if they sign White and he inevitably gets injured that still doesn't mean big PT for Burke. Yes, they are committed to Biggio at 2B so it won't be there unless Biggio gets hurt. Bagwell will at least have the right-handed half of a platoon at first, but remember they will also be finding at bats for the newly re-signed Mike Lamb who they really gave a lot of at bats to in the 2nd half of last year and who is one of their few power guys. This scenario would leave Berkman in LF.
As much as I think Burke is an exciting option, it just isn't safe to guarantee him even 300 plate appearances this year. It would take injury(ies) or big slumps by Lane or Tavares to get him those ABs.
“Most men lead lives of quiet desperation and go to the grave with the song still in them.” --Henry David Thoreau