Mizuno base layers are on the slimmer side but, unlike other base layers, they’re not exactly classed as ‘slim fit.’
The brand prefers to use the term ‘athletic fit.’ This is to emphasise the fact that Mizuno base layers, while slimmer than your standard t-shirt, aren’t completely compressing the skin on all sides.
Rather, enough wiggle room is left for the player to feel as comfortable and free as possible, while still being supported.
It’s this quality that may let you wear a Mizuno base layer as your top layer, if you prefer, and if the weather allows for it, when compared to other base layers.