With the Rams prepping for Sunday's home game against New Orleans, there's been plenty of attention given to Saints defensive coordinator Rob Ryan.

You know the story: Rams head coach Jeff Fisher hired Ryan to run the Rams defense … except that he didn't.

The bizarre Ryan-Rams relationship ended in a quickie divorce, with Ryan immediately hooking up with the Saints. And Ryan has done a very good job of supervising an improved New Orleans defense.

While the story line is understandable, I'm much more interested in the play of the Rams defense under first-year coordinator Tim Walton.

Forget Ryan.

Not enough attention has been paid to the Rams' defensive decline. 

Compared to last season, the 2014 Rams are giving up more points, more yards from scrimmage, more overall touchdowns from scrimmage, more touchdown catches, more yards per completion, more yards per touch. The passer rating against the Rams defense is up, as is the completion percentage and the yards per passing attempt. The TD/INT ratio allowed by the Rams has gotten worse, as has the percentage of making successful stops on third down.

The one positive: The Rams have improved their performance against the run this season. They lead the NFL in the percentage of “stuffed” running plays, and have lowered their average yield per rushing attempt from 4.3 yards last season to 3.9 this season. That average of 3.9 yards allowed per run is the eighth-best by an NFL defense.

The Rams are among the best pass-rush teams, ranking tied for seventh in sacks (38) and No. 3 in the percentage of passing plays that result in a sack (8.4 pct.) So the big men up front are getting it done. They've improved at jamming the running lanes, and Robert Quinn and Chris Long bring the pass-rush heat.

The problem? When the Rams don't generate a pass rush, they're pretty much helpless to stop the forward pass.

We're talking about a historically bad pass defense here.

In terms of completion percentage against a defense, we're seeing one of the worst performances on record. With assistance from STATS LLC, I did some research on this and will pass along the findings.

Highest completion percentage allowed in a single season:

* 2011 Indianapolis, 71.1 percent.

* 2007 Detroit, 70.1 percent.

* 2013 St. Louis, 68.5 percent.

The opponents' passer rate of 97.2 against the 2013 Rams is the 34th highest (as in “worst” ) against an NFL defense in league history.

That 97.2 passer rating is also the highest (worst) allowed in franchise history, going back to the Cleveland Rams days. 

The Rams' average of giving up 8.36 passing yards per attempt is tied for the 41st highest (worst) in league history.

The 8.36 Y/A is the second-highest (worst) in franchise history; the '91 Los Angeles Rams gave up 8.43 yards per attempt. 

And obviously the 68.5 pct. completion rate is the highest against a Rams team in franchise history. 

It's astounding to me how a defense that regularly disrupts quarterbacks can be so awful against the pass. A strong pass rush is supposed to benefit the secondary and tighten the pass defense, right? 

Well, the 2013 Rams are flipping that theory upside down.

Let's have a look at specific areas and players; all stats culled from the excellent web site, Pro Football Focus

CORNERBACKS

Janoris Jenkins, Trumaine Johnson, Cortland Finnegan (now on  injured reserve) and rookie Brandon McGee have given up a 67.4 completion percentage, 1,497 yards and 8.7 yards per attempt. They've been hit up for 12 touchdown passes with four interceptions. The passer rating against Rams' corners is a hideous 108.1.

Johnson is the only corner that's played pretty well; the passer rating against him is 79.3 Now in his second NFL season Jenkins has been a huge disappointment; quarterbacks have zinged him for 50 completions in 75 attempts with four touchdowns (and one INT) for a passer rating of 116.6.

SAFETIES

Rodney McLeod, T.J. McDonald, Darian Stewart and Matt Giordano have been targeted 51 times and given up 41 completions (70.6) percent. They've allowed 10.6 yards per passing attempt and have been burned for a passer rating of 102.5. McDonald, a rookie, has a chance to become a good safety. But this season quarterbacks have completed 12 of 15 passes against him with two touchdowns.

OUTSIDE LINEBACKERS

Rookie Alec Ogletree and veterans Jo-Lonn Dunbar and Will Witherspoon have been exploited repeatedly on the under routes; quarterbacks have hit on 81 passes against them on 93 targets for an insane rate of 87 percent completions, with an average of 10.25 yards per attempt.

Ogletree has the potential of developing into a special talent, but opposing offensive coordinators and quarterbacks are taking advantage of his inexperience by picking on him. They've completed 57 of 68 passes against Ogletree when targeting him; that's a 70 percent completion rate. Among the league's 4-3 outside linebackers, Ogletree has given up the most total yards passing (699) and yards after the catch (560.)

MIDDLE LINEBACKER

Quarterbacks have completed 35 of 48 on James Laurinaitis. But when targeting him they have no touchdowns and two interceptions. And Laurinaitis has done a a good job of containing the yards after the catch. Overall, JL grades out decently for his overall coverage. Pro Football Focus ranks him 13th in conerage among 4-3 middle linebackers.

Despite having the assistance of one of the league's best pass rushes, why is the Rams' pass defense so poor and porous?

1. Obviously, there's a talent gap in the secondary. I'm assuming Fisher and GM Les Snead will put a high priority of reinforcing the area by drafting or signing corners and safeties. They can't ignore such a glaring weakness.

2. Much of this is attributable to inexperience. The secondary is very young and easily exploitable. As a coverage LB, Ogletree will get better. The safety McDonald should get better but there are no guaranteed. After all again, we thought Jenkins would improve in his second NFL season. And he hasn't.

3. The Rams have to make better decisions; that $50 million free-agent investment in Finnegan hasn't worked out as expected. And the Rams released safety Quintin Mikell after last season; he's starting for a championship-caliber defense in Carolina. (Mikell, however, isn't effective against the pass. He's a box safety and a good one.) 

4. Walton is still in the process of proving himself as a coordinator. I liked his hiring as Rams defensive coordinator. Walton is a promising young coach. But all coaches are accountable for performance, and the Rams' pass defense is terrible. Before joining Fisher's staff Walton ran the Detroit secondary for four seasons; over that time the Lions ranked 22nd in yards allowed per passing attempt (7.28), gave up the fourth-most TD passes (110), and were 31st in allowing a 92.3 passer rating. Based on the body of work, I think it's fair to scrutinize Walton's acumen in stopping a passing game.

The Rams figure to be under duress on Sunday. Saints quarterback Drew Brees ranks second in the NFL in passing yards and touchdown passes (33) and is completing 68 percent of his throws. The Saints present acute matchup problems for the Rams because of Brees' ability to spread the ball around to many targets.

Wideout Marques Colston has 56 receptions. Jimmy Graham leads NFL tight ends in catches (74), receiving yards (1,046) and touchdowns (14.) Running backs Pierre Thomas and Darren Sproles have combined for 122 receptions, 959 receiving yards and five TD grabs.

That's a lot of targets.

That's a lot of receivers to account for.

I wouldn't worry too much about Rob Ryan.

The Rams have many other things to worry about Sunday.

Thanks for reading …

— Bernie

Watch "Breakfast with Bernie," each weekday, sponsored by Papa John's, where you get 50 percent off regular price menu items the day after a Blues victory in which they score 3 goals. Use promo code "BLUES3" at checkout. 10% of purchase price benefits Siteman Cancer Center.

Bernie Miklasz is a sports columnist for the St. Louis Post-Dispatch.