One thing that is synonymous with St Patrick's Day is McDonald's Shamrock shake.
The 2012 Pittsburgh Pirates had more members with a surname that began with Mc__ than any other team I have seen before.
Also on the sign is Casey McGehee
Not on the sign, but eligible to be on it because he played for the 2012 Pirates is Catcher Michael McKenry, Utility Infielder John McDonald, Starting Pitcher James McDonald, and Pitcher Kyle McPherson.
That's 8 Mcs