The top of the rotation was Beckett, Lackey and Dice-K. In 2009, those guys were good enough that you shouldn't have needed a #2. Penny and Smoltz were 5/6's at best. I don't think anyone really expected Penny or Smoltz to be anything more than roster filler. This was a team that almost made the WS in 2008. It's not like they were a bunch of pieces away.
edit: I meant Lester, not Lackey. Sorry.