Not only is Rob Gronkowski’s knee injury not as severe as initially believed, “Gronk” could be back on the field as soon as this Sunday against the Philadelphia Eagles (4:25 p.m., FOX). Gronkowski was carted off the field in the fourth quarter Sunday night in Denver during the Pats’ first loss of the season, but NFL Network’s Ian Rapoportreported Monday that the burly tight end suffered no structural damage in his knee. The Patriots may opt to err on the side of caution with Gronkowski considering his injury history, and given that the 4-7Eagles are one of the weakest teams left on the regular season schedule. These next few weeks will be crucial, however, in terms of playoff positioning for the Pats in the AFC as Denver now owns a tie-breaker with the Pats. The Broncos have just one more loss on the year than the 10-1 Pats. The Pats’ next “big” game is Sunday, Dec. 13 against the suddenly relevant Houston Texans. With Houston now in the AFC playoff mix, the game has been flexed from a 1 p.m. kickoff to the Sunday night game on NBC (8:30 p.m.).