Probably more than any other position in fantasy baseball, the value of relief pitchers is largely based on factors beyond whether or not they're actually particularly good at what they do.  Value is often determined by opportunity rather than pure performance.  And somewhat counter-intuitively, sometimes the guys who get the most chances aren't playing for the teams that win the most games.

This week, I take a look at the closer situations throughout the American League, from the most secure to the least.

SECURE

Anaheim Angels -- Francisco Rodriguez

Rodriguez is about the best there is right now, and he's been extremely consistent since becoming a closer in 2004.  Scott Shields would take over in the event of an injury, and likely do a very solid job, as well.

Minnesota Twins -- Joe Nathan

Hard to imagine that this guy didn't really hit the majors for good until he was twenty-eight. His performance has bordered on the absurd. Juan Rincon or Jesse Crain would likely fill-in if needed.

New York Yankees -- Mariano Rivera

Eventually, Rivera is going to turn out to be human. Just go out and get him on your team and hope it's not this year. In the event Rivera gets hurt, total mayhem ensues with Kyle Farnsworth or Scott Proctor.

Toronto Blue Jays -- B.J. Ryan

Hard to argue with the results of signing this guy. Might get a few more chances if the team improves in its second year after the big free agent splash. Brandon League is an interesting backup, but he is a bit green.

PRETTY SECURE

Oakland A's -- Huston Street

Street's inflated ERA last year was probably a fluke, as his peripheral numbers still place him near the top of the closer heap. However, he's got Justin Duchscherer right behind him, so he needs to recover from a tough finish to the postseason.

Seattle Mariners -- J.J. Putz

Something clicked for Putz last year, who managed to basically double his strikeout totals while cutting his walks in half last year. The numbers for last year say he was off the charts effective, but his previous numbers make 2006 look improbable. Chances are that he continues where he left off.

Baltimore Orioles -- Chris Ray

The only thing particularly suspicious about Ray is rather uncloser-like strikeout totals and strikeout to walk ratios. The Orioles made a lot of effort to improve the pen around him, which may or may not work. Dannys Baez is next in line, but has failed in enough other places to be an unreliable choice.

Chicago White Sox -- Bobby Jenks

Jenks allows a lot more baserunners than most of his brethren. His security is based more on a lack of experienced alternatives than anything else. Like Jenks, though, the Sox setup guys will throw hard.

Detroit Tigers -- Todd Jones

Jones is the perfect contrast to the hard throwers that set him up. However, he wasn't even the best reliever on his team last year. Either Joel Zumaya or Fernando Rodney could seize the job here during the season if Jones gets hurt or falters.

Kansas City Royals -- Octavio Dotel

Sure, he hasn't been effective since early 2005, prior to a major arm injury. Luckily, the Royals have no other alternative. He'll have time to work the kinks out.

INSECURE

Texas Rangers -- Eric Gagne

Gagne's injury history makes him risky. While he's probably a better bet to perform than Dotel, he's got Akinori Otsuka right behind him, coming off a very solid year at closer.

Cleveland Indians -- Joe Borowski

There simply have to be a lot of red flags about this guy's arm. Normally, coming off a 36 save season and entering a free agent class that lacks closers when demand for closers is high, you'd see a bidding war. Instead, he ends up with a one year guaranteed contract and no promise of a job. Keith Foulke's retirement helps clear the situation, but Rafael Betancourt or Roberto Hernandez could end up closing.

Boston Red Sox -- Joel Piniero

The best that can be said about this little experiment is that Piniero can't do any worse than he did as a starter last year. This is a situation that will probably be in flux into the regular season, with Mike Timlin, Craig Hansen, Julian Tavarez, and Brendan Donnelly. Who do I think wins out in the end? I think Jonathan Papelbon will find his way back into the role during the season.

Tampa Devil Rays -- Seth McClung

Like Piniero, there are reasons his stuff and makeup could translate in the closer role. There are also reasons he's failed as a starter thus far. Stay away until the very end of your draft, and then monitor the situation very closely.