I need for you to be on time for practice or you will be cut from the team.
Explanation:
When she/he says "You are always late for practice." I think they are saying, that they are a little upset because they joined the team to be a part of it, but when they always show up late, they miss out a lot of the instructions and they're behind. If they continue being late there will be no point for them to show up at all.