The host Pittsburgh Steelers and Philadelphia Eagles, who meet Sunday in the western end of Pennsylvania, are coming off strikingly different weekends.The Eagles (1-2-1) rode a strong fourth quarter to a 25-20 win at San Francisco.Pittsburgh (3-0) had an unexpected weekend off. The Steelers’ scheduled game against Tennessee was postponed to Week 7 because of the COVID-19 outbreak that hit the Titans organization, so Pittsburgh’s bye week was moved up to Week 4.That was not ideal, according to Steelers quarterback Ben Roethlisberger, who has had a strong start — he’s thrown for 777 yards and seven touchdowns with one interception — in coming back from elbow surgery in an offense that has improved over its three wins.The Steelers’ momentum might have taken a hit, he said.”I guess I am going to just start over from scratch and hope this week I didn’t take too many steps backward,” Roethlisberger said.”That is tough, especially someone like myself who was just starting to get back in the flow of things. It’s not easy, but you’ve got to adjust. You’ve got to adapt and do the best you can.”Steelers defensive tackle Cam Heyward called the past week “a whirlwind. … A lot of things happen on the fly. We’re just trying to adapt to the situation.”Pittsburgh already was relatively healthy, so the open date didn’t help a lot there. Receiver Diontae Johnson has graduated from concussion protocol, although he missed practice Wednesday because of a toe problem. Fellow receiver Juju Smith-Schuster (knee) also missed Wednesday’s practice. Neither has missed a game while dealing with those injuries.Also not practicing for Pittsburgh on Wednesday were fullback Derek Watt (hamstring) and linebacker Marcus Allen (foot).While any team would find it prudent to respect Pittsburgh’s offense, Philadelphia is concerned about the Steelers defense.Specifically, linebackers T.J. Watt and Bud Dupree could present challenges to the Eagles’ passing game, especially against an offensive line whose members have fluctuated so far.