Possible Clues:

• 'How 'bout them ___?' (classic conversation segue)
• "Amazin"' team
• They play at Shea
• Baseball team whose original full name is rarely used
• Two-time Cy Young winner Jacob deGrom and teammates
• Shea denizens
• Team whose mascot's head is a ball
• Big Apple ballplayers
• "Miracle" team of 1969
• Citi Field ball team