Brian Elliott, who lead the NHL this year in save percentage (.930) and nearly in GAA (2.07, bested by Ben Bishop's 2.06), will get a chance to win his second playoff series as a Blues. Elliott, who you may remember as the only Blues goalie to win a playoff series since 2002, had a hell of a streak to win the season, being given credit for the loss in just one of his last 12 starts.
With the injury to Jake Allen, the annual "who is the playoff starter" debate suddenly became a moot point - it certainly wouldn't be Anders Nilsson. Had Allen remained healthy, though, you'd be hard pressed to be angry at Blues fans for wondering who Ken Hitchcock would go with to start the playoffs. He has appeared hesitant to start Elliott, even when his play warranted it, and the franchise has gone out of their way to get "5% better" instead of going with who they have in net.
You could make the argument that Brian Elliott's earned this right to start in the past. You can also point at his playoff stats, which aren't exactly stellar - but then, neither were the Blues' performances as a team those series. As of right now, Brian Elliott - and the rest of the team - have been playing lights out hockey and stand a decent chance of taking out the defending Stanley Cup Champions. Just roll with it.