I don't think the Blazers fear the Spurs at all; they've matched up very well with them the last few seasons. On the other hand the Blazers have never gotten a dose of "Playoff Spurs" either.
These are the keys to series in my mind (assuming LaMarcus is his usual dominant self and Wes, Nic and Rolo all play well):
1. Can Lillard hang with Parker on the defensive end? He doesn't have to shut him down, but if they are constantly switching him off onto Leonard or somebody else to "hide" him, the Spurs will be like a boxer continually jabbing at a cut on his opponent.
2. Can the bench produce at least 20 points per game and play somewhat passable defense? The Blazers' X-factor is Thomas Robinson; they really need him to be able to contribute 15-20 good minutes per game, and we desperately need "good" Mo to show up
3. Pop is the best coach in the game. Can Stotts at least play to a draw on his adjustments, moves and counters during the series? If yes, then the Blazers might steal a game or two in San Antonio.
All in all, I think the Blazers match up pretty well, but just don't have the roster depth and playoff experience to be anything other than an underdog, especially without home-court, but if they get a few breaks and some guys play way over their norm (Lillard on defense, Robinson being reliable for more than 5 minute stretches, and Mo playing within himself) they've got a puncher's chance of stealing the series.