Brian Wilson: Are San Francisco Giants Closer's Days Numbered?

Having saved 19 games for a contending club by June 20 is business as usual for an All-Star closer. Brian Wilson, the San Francisco Giants' enigmatic, bearded show-stopper, is used to finishing off opponents in the ninth inning on a frequent basis with great success.

But now that Wilson is out for the season after undergoing Tommy John surgery, he's had to watch from the bench as his bullpen mates try to pick up the slack by closing out games for a club that plans on playing October baseball again after an injury-plagued 2011 kept them out of the postseason.

And pick up the slack they have. Or more specifically, he has. He is Santiago Casilla, San Francisco's hard-throwing right-hander who, prior to this season, was used by Bruce Bochy primarily as a setup man alternating with Sergio Romo.

Casilla has thrived in his new role, having converted 19 out of 20 save chances, posting a 1.32 ERA and 1.02 WHIP in the process. In 27.1 innings pitched, he's struck out 23 and walked eight. Currently second in the league in saves, Casilla is on pace to close out 45 games for the Giants, and seems to have locked up the closer role with his All-Star-caliber first half thus far.

While both Casilla and the man he replaced as San Francisco's closer are eligible for arbitration next season, followed by free agency in 2014, their futures will now be inextricably linked and dependent upon one another.

That's because the more Casilla performs in 2012, the more intense the closer competition will be next season in San Francisco, with Wilson presumably returning in 2013 and Casilla now a proven quality closer.

Ultimately the question of who will be the Giants' closer in 2014 and beyond may come down to which of the two is more affordable for a club already contractually leveraged with starter Matt Cain's recent $127 million extension and potential extensions for Tim Lincecum and hot-hitting outfielder Melky Cabrera.

While Casilla and Wilson may be in competition for the closer's role on the field next season, they certainly don't start out on an even plane when it comes to salary in 2012. While Wilson is making over $8 million this year, Casilla is earning just $2.2 million.

Given Casilla's probable lower price tag come free agency (due to the fact that even if he puts up great numbers this season and next, he has a shorter track record and less media appeal than Wilson), it's conceivable that the Giants could part ways with The Beard.

Only time will tell, and there are many variables. One big one is Wilson's health: will he be the same dominant flame-thrower he was in 2010 after recovering from surgery?

One thing's for certain: Santiago Casilla's success is raising the specter of quite the "closer controversy" for the Giants come spring training 2013.