YES Network.com

Although he may be the most successful closer in Major League history, Mariano Rivera spent his hump day actually "starting" for a change.

On Wednesday morning, Rivera rung the opening bell to signal the beginning of the trading day at the New York Stock Exchange, and followed that up with a furious version of the customary closing gavel bang – proving that even though his knee may be injured, his right arm is as lively as ever.

You can check out the video of The Sandman’s stock starter below, courtesy of the NYSE.