The Yankees added a terrific pitcher who will be helping with his brain instead of his arm.

Andy Pettitte has been brought in as an adviser, The Post confirmed, bringing a lifetime of pitching and big-game excellence back to the franchise.

Pettitte, who retired following the 2013 season and who pitched 15 years with the Yankees in which he won five World Series rings (1996, 1998-2000 and 2009), was part of the large contingent who watched Jonathan Loaisiga pitch against Aaron Judge during Sunday’s simulated game.

The lefty is immortalized in Monument Park.

The addition continues to signal an added emphasis on experience, perhaps at the expense of analytical expertise.

After a brutal first half in which their bats underperformed, the Yankees fired hitting coach Dillon Lawson, who did not play in the majors, and replaced him with longtime slugger Sean Casey.

The Star-Ledger/NJ.com first reported Pettitte’s hire.