The general membership of the Maine Principals’ Association will vote Thursday morning on proposed classification expansion for high school football, volleyball and lacrosse.

Those decisions will be the first order of business at the MPA’s annual two-day spring conference at the Samoset Resort in Rockport.

In football, the proposed addition of a new fifth class will be decided. It is designed primarily to help four schools that have dropped varsity football since 2013 – Boothbay Region, Camden Hills, Sacopee Valley and Telstar – return to varsity status. As proposed, Traip Academy and Maranacook would complete the new six-team Class E.

The football proposal also shifts enrollment figures. While Class A would remain unchanged, several teams would move from Class B to C and others from Class C to Class D.

Separate proposals out of the classification committee are calling for volleyball and lacrosse to add a third class. Both sports have seen a growth in the number of schools offering varsity teams over the past decade. The volleyball’s new Class C would have the effect of creating a separate division for the nine Down East teams plus North Yarmouth Academy.

Lacrosse’s proposed Class C would be for schools with fewer than 600 students and would also accommodate new or developing programs regardless of school size.

Also on the docket is a proposal to change the way co-operative teams’ enrollment is counted. Currently all co-operating schools’ enrollments are added together. The new system would count a percentage of each “attaching” school’s enrollment equal to the percentage of students it supplies to the total roster.

Proposals pass with a majority vote, with each school getting one vote. Any changes would take effect for the 2017-18 school year.