So Mark Anderson is gone. Another defensive experiment has gone out the door. We barely got to know the guy. Anderson swept through here like a ghost, leaving scarcely any evidence of his physical being.

Anderson was seen as a partial solution to the Bills’ pass rush woes, a nifty accessory to Mario Williams. He hurt his knee and wound up playing five games a year ago. Anderson was barely noticeable in the games he did play. He finished with 10 tackles and one sack.

For that, Anderson pocketed $8.1 million. Nice work if you can get it. His release came as a mild surprise. Evidently, the new regime reached the same conclusion Bill Belichick did when he decided not to re-sign Anderson as a free agent after the 2011 season. He wasn’t worth the investment.

Anderson had 10 sacks in the ’11 season, helping the Patriots reach the Super Bowl. Those sack numbers were too much for the Bills to resist.

They’ve thrown a lot of money at pass rushers over the years, like a bad gambler who can’t pull himself away from the craps table.

Buddy Nix wasted $10 million on Shawne Merriman, hoping Merriman would regain his old form. The Bills spent millions on Aaron Schobel and Chris Kelsay and couldn’t get a consistent rush with four men. They handed Mario Williams a $100 million contract, with little tangible reward.

The Bills squander more than $18 million on Merriman and Anderson, but they play contract hardball with a home-grown star and Pro Bowler, safety Jairus Byrd.

Remember that the next time they talk about “paying for production.”

They keep gambling on other teams’ castoffs, and the defense keeps getting worse. A year ago, despite all the investment, they gave up 435 points, second in team history to the ’84 squad. The 2011 (434) and 2010 (425) teams hold down the third and fourth spots in franchise history in points allowed.

Nix did a woeful job of building a defense in his three years as general manager. Doug Whaley, his successor, has to take his share of the blame. Whaley has been with Nix from the start. He has had influence on the college and pro personnel side. Where’s the evidence of his personnel genius?

Well, they can always blame the defensive coordinators. Dave Wannstedt was bad; we know that. Still, listening to Nix, you’d think Wannstedt was holding back some defensive powerhouse. But they were very bad. It’s amusing to hear people talk about how much they improved later in the season.

The Bills went 6-10 last season. In NFL passer rating, the six teams they beat finished: 32nd (Arizona); 31st (K.C.); 30th (Jets); 29th (Cleveland); 28th (Jacksonville); and 26th (Miami). Ten of their 16 games came against the bottom eight-rated passing teams in the league.

As far as I’m concerned, they didn’t stop anybody. Talk to me about Mario Williams’ sack total when he has a dominant game against a top offense.

Oh, but things are bound to get better with Mike Pettine running the defense. He did great things with the Jets. It’s good to hear Pettine talk about attacking, about moving people around and being less predictable before the snap.

The Bills will be more aggressive and creative on defense. It’s not a novel concept in the NFL – unless you hand control of the defense to the likes of Wannstedt and Dick Jauron, who are still stuck somewhere in the 1980s.

All the chatter about attacking defense sounds familiar, doesn’t it? Gregg Williams talked that way when he took the head coaching job here in 2001. Williams was a cutting-edge genius, too. He promised to be aggressive and predicted record sack totals. Then a lack of talent got in the way.

In the end, it always gets back to talent. Coaching matters, of course. I’m on board with the new coaching staff. It’s a refreshing change to have new ideas and youthful energy in the franchise. But new ideas don’t pressure opposing quarterbacks; elite players do.

It’s become a learned reflex for Buffalo sports fans to assume the best. The need for belief is always greater than the reality. Slap a new coat of paint on an old junker and people want to believe it’s going to run better.

But look at the roster. There are so many holes. They’re still counting on Torell Troup and Alex Carrington to be players. Aaron Williams and Leodis McKelvin are penciled in as starters on defense. Kyle Williams isn’t the same athlete he used to be. Marcell Dareus hasn’t lived up to his draft position.

They’re rebuilding and getting younger on defense. They’re expecting Jerry Hughes, who came in the trade for Kelvin Sheppard, to blossom as a rush linebacker. They’re high on Jamie Blatnick and Marcus Dowtin, undrafted free agents who were let go by other teams.

I’ve heard more than one person suggest that rookie inside linebacker Kiko Alonso could be the key to the defense this season. It tells you something when so much is riding on the shoulders of the 46th overall draft pick.

Of course, it’s not so rare for later draft picks to have an immediate impact on a defense – in other cities. Bobby Wagner went 47th overall to the Seahawks in 2012 and was one of the top inside linebackers in the league as a rookie for a playoff team.

It’s all about picking the right players, something the Bills have done with little regularity in recent years. Pettine talks tough, but if the last three years are any indication, he has a daunting task on his hands.

Luckily for Pettine, the standard is low. It must be some comfort to know that giving up fewer than 400 points will qualify as progress.