Getty Images says:
Tommy Agee #20 of the New York Mets slides into third base against the Chicago Cubs during an Major League Baseball game circa 1969 at Shea Stadium in the Queens borough of New York City.
Yes, that’s Agee, and yes, that’s Shea, and yes, it’s against the Cubs, and yes, he is sliding into third base.
But it’s definitely not 1969. Why? Because you don’t see the 1969 baseball centennial patch on Ron Santo’s jersey.
So this has to be from 1970 or 1971, because those are the only other two years the Cubs wore that style of road uniform.