Hi Tianyi, I'm sure someone much more experienced can give you a better anwser, but usually that's not too good. Speed for a C (keep in mind, the positions listed aren't where they have to play) isn't too critical in most coaches opinions, but ATH tends to positively or negatively impact a players performance a lot.
Also remember your offense/defense. Since you run man to man, slow, un-athletic players may get schooled on the defensive end, even with a high DEF rating.
Hopefully someone with a much better record than mine can offer more insight, as you can see I'm just painfully average

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