Sabbatical leave

Im planning to go for master in december. First day of college is on 10-jan(mentioned in offer letter). So if i apply for sabbatical leave, can i use all my sick leaves and earned leaves before going on sabbatical leave.im having 30 EL and 15 SL. And in tcs if we ask for sabbatical leave from which date they will provide which ever the date we requested for?