(My apologies for putting an Angel as the main picture. You'll see why and smile in a moment. Trust me.)
By now, you've probably figured out that the most valuable players to the Athletics (and hey, I can use most valuable because the A's made the playoffs, and that's the only stat that matters) were Josh Reddick (4.8 fWAR) and Yoenis Cespdes (3.1 fWAR).
But no one is talking about the guys who contributed absolutely nothing. Luckily, the A's didn't have players who were that bad this year. The least valuable player, using Fangraphs WAR, was actually Dan Straily at -0.5 fWAR. The surprising minor-league strikeout machine had a slightly-below average 3.89 ERA with Oakland, but that masked a ghastly 6.48 FIP (fielding independent pitching).
I'm pretty sure I've already lost Mitch Albom.
Next was third baseman Luke Hughes, who played in all of four games but managed to do the complete opposite of what catcher George Kottaras did in 27. Hughes finished with an fWAR of -0.4, getting one hit in 13 ABs. Brian Fuentes (yeah, it's easy to forget that he pitched for the A's in 2012) also had an fWAR of -0.4, but I'll forgive him, as "helping an incompetent manager get canned," doesn't really show up in the stat sheet. For that, we thank you. Enjoy retirement, Brian.
And now for the least valuable players in baseball (among qualified players):
5. Brian Roberts (BAL), Eric Hosmer (KC): -1.1 WAR
4. Jeff Francoeur (KC): -1.2 fWAR
3. Ryan Lavarnway (BOS), Brennan Boesch (DET): -1.3 fWAR
2. Michael Young (TEX): -1.4 fWAR
1. (tie) Casey Kotchman (CLE), Ryan Kalish (BOS), Ryan Raburn (DET): -1.5 fWAR
Remember when the Andrew Bailey/Ryan Sweeney for Josh Reddick, etc. trade went down, and fans wanted Kalish or Lavarnway? Yeah, I think Reddick was the right choice.
It's also worth noting that the only qualified pitcher who finished with a negative fWAR was Ervin Santana. Santana last year posted a solid 2.9 fWAR season (and isn't too far removed from his 5.8 fWAR 2008 season) ... but absolutely plummeted this year to -0.9. Ervin Santana was worth a NEGATIVE $3.9 million in 2012. The Angels would have been better off pickpocketing Santana and then giving him the wrong flight information for road games.
If you ever need a pick-me-up after a rough day, you can assure yourself that you are probably worth more than negative $3.9 million to your company.
My apologies if Santana is reading this. That would be awkward.
5. Miguel Cairo (CIN), Matt McBride (COL), Ryan Howard (PHI), Alex Hinshaw (SD/CHC): -1.0 fWAR
4. Greg Dobbs (MIA), Eric Hinske (ATL), Dee Gordon (LA), Wilson Valdez (CIN), Lucas Duda (NYM), Trevor Pastornicky (ATL), Josh Lindblom (LA/PHI): -1.1 fWAR
3. Josh Vitters (CHC), Chris Coghlan (MIA): -1.2 fWAR
2. Bryan Peterson (MIA): -1.3 fWAR
1. Joe Mather (CHC): -1.5 fWAR
Also of note... worst qualified Athletics in the Oakland era:
5. Billy Williams (75-76): 1.8 fWAR
4. Bobby Kielty (04-07): 1.1 fWAR
3. Mario Guerrero (78-80): -0.3 fWAR
2. Rob Picciolo (77-82, 85): -1.9 fWAR
1. Ruben Sierra (92-95): -2.4 fWAR
5. Todd Van Poppel (91, 93-96): 0.6 fWAR
4. Mike Mohler (93-98): 0.5 fWAR
3. Dave Wengert (95-97), Carlos Reyes (94-97): 0.3 fWAR
2. Tim Conroy (78-85): -0.3 fWAR
1. Lew Krausse (68-69*): -0.4 fWAR
*Krausse pitched for the A's from 61-69, but I'm just looking at players who pitched for the organization in Oakland. Krausse's total body of work for the franchise is actually worth a 2.4 fWAR value.