Kevin attended Yankee game back in June while in NYC...

oscaralvarez84 - Oscar Alvarez Yañez: Yankees #yankestadium #yankees #baseball #kevincostner @kevincostnermodernwest (Posted June 17th)
https://www.instagram.com/p/By1mcLxCNsI/

iamnysports - John Broder: #kevincostner @yankees @yankeestadium #baseball #ilovebaseball #ifyoubuildittheywillcome #pinstripepride #bronxbombers #yankees #yankeestadium #staypositive #believe (Posted June 18th)    https://www.instagram.com/p/By2xHwrnJKM/

stirburgers - Duke von STike: New York Yankees vs. Tampa Bay Rays with Kevin Costner 😎 #baseball #newyorkyankees #yankeesstadium #stirburgersnatripu #kevincostner #newyork #nyc #usa (Posted June 18th)
https://www.instagram.com/p/By2hEa7CZXf/

New York Yankees ‏Verified account @Yankees tweeted: Is this heaven? (Posted June 17th)
https://twitter.com/Yankees/status/1140783301843738625

Erica Wheeler‏ @ericalouwheeler tweeted: OMG!! I’m in the same stadium as #kevincostner !!!!! @kevincostner I’m dying!! Biggest fan! Seriously freaking out! #yankees #NYC @modernwest (Posted June 17th)
https://twitter.com/ericalouwheeler/status/1140787996171612163