It’s been mostly happy thoughts around here for the past month-plus, as the Redskins have embarked on a five-game win streak and moved themselves from 3-6 into first place in the division. Even the most rigid of doubters has come around on this team.

Have you considered how you’d feel if the good times don’t last? Or how, if the Redskins — in good position to end up in the playoffs — might come up short? We haven’t discussed it much in this space.

(Associated Press)

If there’s one reason to worry, it’s no longer the maligned secondary or the fact that Robert Griffin III might or might not play. Suddenly, a remarkably stable offensive line could be down as many as three players — starters Will Montgomery and Tyler Polumbus, and reserve Jordan Black (suspension) — for Sunday’s game or beyond.

That could lead to a relatively successful season unraveling at the end. Are you worried at all about that possibility?

Mike Shanahan doesn’t sound worried. It could be coach-speak of course, but in Mike Jones’s Tuesday story about the O-line, Shanahan praised the depth that he’d drafted over two years, and noted that different line combinations rotate in during practices. If the man who studies these players as closely as anybody is confident, maybe you should be too. Then again, what else do you expect a coach to say? “We’re going to be in a world of hurt out there, no doubt about it?”

In the best-case scenario, Griffin, who says he could have played last week, starts against Philadelphia and shows no ill effects from the injury suffered against the Ravens. But all it takes is just one line miscommunication for him to get banged up again.

The Eagles’ defensive ends aren’t lining up in the wide-9 technique anymore, and Jason Babin was released and picked up by the Jaguars. But they still have the normally relentless Trent Cole, finishing up one of his statistically worst seasons, and Brandon Graham, a high draft pick in 2010 who has four sacks and a forced fumble the past three games. In Week 17 against Dallas, the Redskins will have to deal with one of the best pass rushers in the league in DeMarcus Ware.

The Eagles and Cowboys are also two teams the Redskins can look to for examples of how a line can impact an offense. Philadelphia’s normally potent unit has come unglued without tackles Jason Peters and Todd Herremans and center Jason Kelce. On the other hand, the Cowboys have 178 more pass attempts than the Redskins (578 to 400) yet have given up only one more sack (32 to 31), a surprising stat given that Dallas’s line is sometimes cited as the reason for its offense’s occasional struggles.

If Polumbus and Montgomery can’t go against Philadelphia, and Black isn’t available as a backup, how do you think the Redskins will be affected? Will the offense continue to hum, or is it a problem that could derail the most promising season in recent Washington history?