Defensive lineman Albert Haynesworth walks off the field with defensive coordinator Jim Haslett at the end of the morning practice at Redskins Park on August 6, 2010 in Ashburn, Va. (Ricky Carioti/THE WASHINGTON POST)

Finally headed back to work, the Washington Redskins have many items on their post-lockout to-do list.

With the NFL’s new salary cap at $120 million, the Redskins will sign rookies and free agents soon in an effort to set their roster for the preseason. Before additions occur, the Redskins should make a cap-friendly move that would undoubtedly improve franchise morale as well: Release Albert Haynesworth or take whatever they can get in a trade.

The moment has arrived to end their toxic relationship. It’s time for Washington to close the book on the biggest free-agent blunder in NFL history.

Removing Haynesworth from the team now makes sense for many reasons, the salary cap chief among them.

The defensive tackle has a salary of $5.4 million this season, $1.8 million more than his 2010 base pay. Haynesworth’s salary would become guaranteed if he’s on the 53-man roster for the first regular season game.

That’s money the Redskins could spend on a player or players who may actually help them.

Last April, all the prorated money in Haynesworth’s deal was eliminated when the Redskins paid him a $21 million bonus. Because of that move, Washington would save $5.4 million off the cap by dumping his contract. There would be no negative cap ramifications for Washington.

Although the Redskins have cap flexibility, more flexibility would only help them in pursuing free agents. Also, it’s not just about having space for signings. More cap room means more trade potential.

And after finishing last or tied for last four of the past five seasons, the Redskins cannot afford to waste opportunities.

Their defense was horrendous last season. The talent level along the line must improve, and if possible, upgrading at inside linebacker and cornerback would make sense. Then there are all of the big holes on offense.

During two disappointing seasons, Haynesworth has received almost $35 million while playing in 20 games. Dissatisfied with his role, he has been accused of insubordination and was suspended for the final four games in 2010 for conduct detrimental to the club.

Combined with his off-field legal issues, Haynesworth has little trade value, though there are still a few teams that would strongly consider offering the Redskins a low-round pick in exchange for him. Tennessee previously offered the Redskins a draft choice for Haynesworth, a two-time all-pro with that franchise, but Coach Mike Shanahan rejected the Titans’ proposal.

Shanahan is believed to be seeking a high-round pick for Haynesworth, which he surely won’t receive, so releasing Haynesworth is Washington’s most viable option to end the long-running drama.

Paid almost $24 million in bonuses and salary last season, Haynesworth occasionally displayed the ability that helped him become the No. 1 player in the 2009 free agent class. Ultimately, though, his differences with Shanahan were too wide to bridge, and his performance suffered.

Haynesworth’s unwillingness to commit to Shanahan’s program — after signing a contract for the most guaranteed money in league history at the time — is unacceptable to Shanahan. The notion of Haynesworth possibly “winning” infuriates Shanahan, people at Redskins Park say.

At this point in this mess, there are no winners.

Haynesworth, 30, has wasted two years of his career, and his reputation within the game has been further damaged. Although Haynesworth, beginning his 10th season, probably would receive another contract if he were released, his options have decreased.

 Washington squandered a fortune on a player who was clearly a bad fit from the day he signed. Keeping Haynesworth on the team and having him inactive every week, as some in the organization have suggested, would only compound the error. The Redskins aren’t good enough to burn $5.4 million in real dollars and waste valuable cap space and a roster spot out of spite.

Retaining Haynesworth is especially risky for Shanahan.

Shanahan had a poor first season with the Redskins, failing spectacularly in trading for quarterback Donovan McNabb and making other bad decisions.

Late in the season, some veteran players privately questioned Shanahan’s motives. Most are tired of the Shanahan-Haynesworth feud, and having Haynesworth on the team simply to show who’s in charge won’t help Washington win football games.

 Shanahan lost supporters in the locker room because of his surprising mishandling of sensitive personnel matters. He potentially risks alienating many players if Haynesworth is still on the team when training camp opens this week.

Worst of all for Redskins fans, the Haynesworth debacle never should have occurred.

People repeatedly told owner Daniel M. Snyder that Haynesworth was wrong for Washington’s defensive scheme. They expressed concern about offering an unprecedented contract. It just didn’t make sense.

Snyder ignored it all, acquiring yet another trophy player.

Haynesworth is to blame, too. He signed a contract. Even if promises were broken about the team’s style of play on defense, an agreement remained in effect for him to play for Washington. It was reasonable for the Redskins to expect Haynesworth fill the role he was assigned.

The Titans built their scheme around Haynesworth and gave him freedom, for the most part, to do as he pleased on the field. The Redskins shouldn’t have signed Haynesworth unless they planned to use him similarly.

Anything else, as we’ve seen, was a formula for failure.

In the NFL, the cap often presents hurdles for clubs that make major mistakes on players. For the Redskins, it should provide the motivation to do something right.