ATT Inc can pull out of its agreement to buy DirecTV if the satellite TV operator is unable to renew a deal with the National Football League to offer the popular NFL Sunday Ticket football package, according to a regulatory filing on Monday. The current DirecTV offer allows subscribers to watch football games outside of their local markets on Sundays. The exclusive package, which costs subscribers up to $300 a year, is an important tool for DirecTV to attract subscribers and the company has said about 2 million people receive the service. In a filing related to the acquisition, the companies said: the parties also have agreed that in the unlikely event that the companys agreement for the NFL Sunday Ticket service is not renewed on substantially the terms discussed between the parties, ATT may elect not to consummate the merger. Investors have been watching closely to see whether DirecTV would renew the Sunday Ticket contract with the NFL, estimated to be worth $1 billion annually, with the potential to rise in value as part of a new agreement.