Ticketmaster said Tuesday that it plans to partner with the National Football League to launch a Web site next year that will allow people to resell their NFL game tickets.

The West Hollywood-based ticketing agency said that the move is an effort to get into the lucrative secondary ticket market. Ticketmaster will make money by charging the seller and the buyer a percentage of the price. Ticketmaster added that the multiyear deal includes branding and promotion for the site. Financial terms were not disclosed.

Ticketmaster already operates 18 separate “ticket exchange” sites for NFL teams, which allow ticket holders to sell their game tickets online. The latest deal calls for moving those sites and four new ones to a portal that is to launch some time next year. Ticketmaster is owned by New York-based Internet conglomerate IAC/InterActiveCorp.

Ticketmaster has seen its sales decline in recent years due to the rising popularity and success of such ticket resellers as StubHub.com, which is owned by eBay.com, and RazorGator.

Ticketmaster said that added security features as well as the official NFL branding should woo prospective ticket buyers and sellers to its site.