Redskins quarterback Robert Griffin III was sacked three times and fumbled twice (losing one) in Sunday night’s 31-16 loss to the Dallas Cowboys. (Wesley Hitt/Getty Images)

The Washington Redskins are a year late and $36 million short.

Last season, a surprising offense led by rookie Robert Griffin III and several veterans enjoying perhaps their last good year were able to overcome the first part of the NFL’s two-year, $36 million salary-cap sanction for salary dumping.

But two straight cash-starved free agent classes and the lack of a 2013 first-round pick as part of the Griffin trade compensation — combined with a crumbling offensive line — have Washington 1-4 and probably heading for 6-10 at best.

And then the real fun will begin: deciding whether coach Mike Shanahan will return after three losing seasons out of four.

If there’s a rat that fouled the Redskins’ rebuilding, it’s New York Giants co-owner John Mara, who led the charge for the sanction that prevented Washington from upgrading annually. Washington was able to survive the penalty for a year, but now it’s costing the team victories.

The Redskins’ 2014 first-rounder is the final payment to the St. Louis Rams for the Griffin trade, but at least owner Dan Snyder can spend heavily in free agency. Then again, the Redskins’ free agent history has been dismal. Great teams grow in the draft and supplement through free agency. The Redskins have proven that repeatedly over the past 20 years by doing the opposite and failing.

The cap sanction has especially hit the offensive line. If your name isn’t Trent Williams — get out. It’s impossible to replace four linemen next offseason, but this unit that seemed crisp last year was actually bolstered by Griffin’s agility. With Griffin slower following offseason knee surgery, the line looks slower, too.

The good news is Griffin appeared decidedly healthier against Dallas on Sunday with nine carries for 77 yards. That 26-yarder down the sideline was the 2012 RGIII everyone has awaited to see all season.

Too bad the play-calling was atrocious. Offensive coordinator Kyle Shanahan has been too conservative, especially in first halves. It’s time for the Redskins to let Griffin be Griffin, if only because the offensive line won’t let him be a pocket passer.

When Griffin spreads defenders, Alfred Morris once again becomes a 100-yard back. Maybe they could even call Morris’ number 20 times per game. This system of Griffin scrambling for his life and throwing off his back foot isn’t working.

The salary-cap hit also prevented retaining special teams captain Lorenzo Alexander. The coverage and return units have simply been abysmal. A little money here would have made a major difference.

This year will be spent serving NFL punishment. But parole comes in 2014 free agency.