How can the Tigers, tied for the fewest number of wins of any playoff team, be among the favorites to win the World Series? 

In part, it's due to the system. Needing to cut a travel day out of the current playoff schedule to accommodate the new Wild Card game, MLB went back to the old 2-3 format for the AL and NL Division Series this year, meaning that the lower-seeded team gets two home games first, followed by three games at the higher seed. 

That's made a difference in who the favorite is considered to be in the ALDS between the A's and Tigers. [Here's what the Tigers players themselves think of a couple of perceived advantages.]

Kevin Bradley, SportsBook Manager for Bovada.LV, explains it:

“With Baltimore upsetting Texas last night the Yankees are the current 4-1 favorites to win the World Series for the first time since the All Star break. This new series configuration has made it a little tricky to set these odds and series odds for that matter. In situations where a team like Oakland has home field advantage but have to play the first two games on the road in Detroit make them significant underdogs to take the series at +135. Whereas with the old system, we would have that series as a pick 'em or even Oakland as small favorites. For this reason Detroit has been the heaviest bet team at 5-1 over the last couple days.”

Here are the current odds, courtesy of Bovada.LV:

Odds to win the 2012 World Series

New York Yankees                    4/1

Washington Nationals                5/1

Cincinnati Reds                         5/1

Detroit Tigers                            5/1

San Francisco Giants               13/2

Oakland Athletics                     15/2

St. Louis Cardinals                    9/1

Baltimore Orioles                       9/1