David Plouffe tries to lower them:

Our path to the nomination never factored in a big day for us on February 5. Rather, we always planned to stay close enough in the delegate count so that we could proceed to individually focus on the states in the next set of contests. We fully expect Senator Clinton to earn more delegates on February 5th and also to win more states.

If we were to be within 100 delegates on that day and win a number of states, we will have met our threshold for success and will be best positioned to win the nomination in the coming months.

Jason Zengerle evaluates the memo's significance:

So, unless the Obama campaign has dreadfully wrong internal polls or is just incredibly stupid (the former more plausible than the latter), look for him to finish well within 100 delegates of Hillary tomorrow. Otherwise, even by Obama's own terms, he will have lost Super Tuesday.

Marc makes a similar point:

Unless every Obama adviser I've spoken to over the past year has out and out lied to me, a big day on Feb. 5 has always been a big part of Obama's nomination strategy. That doesn't mean they always expected to win it...just that, for months, the campaign devoted unusual amounts of resources to building robust organizations in the states...and claims 75,000 active volunteers.

Seems like the Obama campaign is setting expectations way low so they can beat them as easily as the Giants front four beat through the line to Tom Brady.