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Shaw has excelled at every other previous baseball level, but to be fair, so has Pedro Ramirez. Ramirez hasn't been as ballyhooed, and I'll admit, I probably slept on him a little more than I should have myself, but Pedro Ramirez has been very good. His worst full-season data came from High-A as a 20 year old where he was still 12% better than average despite being well below average age-wise.
Shaw does have an advantage in terms of sprint speed, so making an argument over who's more athletic, you can point to that. Defensively? It's a lot harder to pinpoint yet. Minor league defensive metrics are essentially non-existent for public consumption. The eye test is wildly wrong most of the time, but Ramirez did win an MiLB gold glove at 3b. So do with that information as you please. Shaw was great at 3b last year and so far in very small samples, Ramirez has been too. I'm not sure there's a clear cut answer to that one yet.