I'm becoming more and more in favor of holding onto him and having him be the OD SS. Gunnar at 3rd. Open contest for 2nd base, Ortiz, Westburg, Urias, whatever.
Mateo's defense is legit, it passes the eye test, the advanced metrics bear it out. And he can hurt teams on the basepaths. If he can get any better with the bat, get that OPS north of .700, that's a valuable guy hitting 9th.
I'm not saying he's a piece for the next 5+ years, there's Jackson Holiday, Ortiz, Westburg and probably others who'll push him out especially if he's not a great hitter. But that defense is something special, I wouldn't be so cavalier in thinking it's expendable.
BuT JoEy OrTiZ!!1111
Spare me.