A Walmart associate can take up to 25 weeks of leave. That's quite a lot of days! However, some rules apply. This is only eligible if you're recovering from a severe injury. They also have Family and Medical Leave Act (FMLA), if either you or a close family member has a serious health condition that needs to be taken care of.
In the event that you have to take FMLA, you will have to use up your 25 weeks in full. Your leave can also be Personal or Military leaves. However, keep in mind that you'll only be given permission for these leaves if you have worked a minimum of twelve months there.