Outfielders Clint Frazier and Aaron Hicks.
Why would the Giants make this trade?
Have you seen their Outfield? It might be the worst in MLB from left, center to right.
Not only are Frazier and Hicks two immediate starters for the Giants, but the upgrades for the Giants would be enormous even with Frazier's yips.
Why would the Yankees make this deal?
First of all, they wouldn't, not until they get Stanton and Judge back healthy, but once that happens, and reportedly it's happening soon, with Encarnacion tying up the DH spot for the most part that means both will have to start in the outfield far more than anticipated, and while Gardner may not be the hitter or even defensive CF Hicks is, he's good enough to do both with the lineup we'll be throwing out there.
As for a forth OF, Maybin has been rock solid and he can play all three OF positions. It might not even be a bad idea to use Gardner and Maybin in a L/R platoon in Center.
Last but not least, we all know the Yankees will have a hard time winning the World Series with our pitching staff as currently constituted. MadBum is a proven winner, highly competitive and he gives us a much better chance to win #28.
Finally, if you think the price is too high, think again. Pitchers like MadBum don't come cheap. The Giants know as well as we do that MadBum can put us over the top and they would love to fix that disaster they call an OF ASAP, so Hicks and Frazier should suffice. You gotta give something of real value to get back something of real value, especially when he can be the missing piece.
As an aside, we still have Estevan Florial coming fast and he looked absolutely terrific in Spring training. It's a shame he got hurt, but he'll be okay and next year he might be our starting CF on the cheap.