Baseball America's Yankees correspondent, George King of the New York Post, is reporting that MLB is investigating two Yankees pitchers, Ivan Nova and Wilkin de la Rosa, for allegedly injecting each other with B-12 shots last season while they were teammates at Double-A Trenton.

Though B-12 isn't on MLB's list of banned substances, only licensed physicians are allowed to inject medication without a prescription. MLB also wants to determine whether the shots were limited to B-12. 

Nova joined New York's big league rotation on Monday and pitched 5 1/3 strong innings against the Blue Jays. De la Rosa still is at Trenton.

For King's full story, please click here.