In our first installment of "Behind Enemy Lines," we talked to Jim Thomas, who covers the Rams for the St. Louis Post-Dispatch. Here are five questions we asked Thomas leading up to the Vikings-Rams season opener at the Edward Jones Dome on Sunday.

1. With quarterback Sam Bradford out for the season, what changes for the Rams on offense with Shaun Hill?

JT: It's obvious that Shaun Hill can't do everything that Bradford could do. Bradford was having a tremendous camp and a very good preseason, which he was really throwing the deep ball well. Overall, he was throwing the ball as well as we've seen him here in St. Louis. As part of the rehab process, he couldn't do any lower body lifting. So he worked on the upper body for weeks and it increased his arm strength.

I don't think they're going to have to trim back the playbook really at all, which they kind of had to do with Kellen Clemens last year. Clemens really had trouble consistently throwing the deep ball. I think they'll have the whole playbook available to him but there's probably some throws where maybe Bradford threw them well and they're maybe not going to emphasize as much.

2. How has running back Zac Stacy looked after an impressive rookie season?

JT: There's high expectations for him. He's got a little bit of a bowling ball physique and a very good interior runner on the outside, on the inside too. He just seems to burrow into that pile and you think he's down, but he got two more yards. He's got pretty quick feet too. He didn't do a whole lot in the preseason. He looked a little heavy-legged like he had some leg weariness, so his stats weren't great.

I'll tell you what, he's being pushed by Benny Cunningham for playing time. Not for the starting job, but Cunningham, an undrafted free agent out of Middle Tennessee State, had a really good camp. His weight is up, gained about 10 pounds and carrying about 220 [pounds], but he hasn't lost any speed. Kind of a similar body style as Stacy but has a little bit more speed and a little bit more wiggle, but he was easily the most impressive of the Rams running backs in the preseason. Although Stacy will get the lion's share of the carries, I suspect you'll see a little Cunningham sprinkled in.

3. What have you seen from the Rams secondary?

JT: ­I think it's the biggest question mark of the team easily. I haven't done the research around the league, but it's got to be the most inexperienced secondary in the league. They have 71 combined starts of everybody in their secondary. And now without Trumaine Johnson (out at least four weeks with a sprained MCL), who wasn't great but has a big body and great athleticism, that's 15 of those starts. They'll have rookie E.J. Gaines out of Missouri starting at one of the cornerbacks spots. Another rookie will be the nickel back Lamarcus Joyner out of Florida State, a second round pick. They're very high on him. He's a small guy, but he's very tenacious tackler, good football instincts in college at least.

Janoris Jenkins, I don't know if he regressed last year but he just didn't make big plays. A lot of penalties, had trouble tracking the deep ball. Again, lots of potential, but he hasn't lived up to the full potential so far. The hope is that with [defensive coordinator] Gregg [Williams] coming, he can come in and get those guys straightened out.

4. How have both first round picks, defensive tackle Aaron Donald and offensive tackle Greg Robinson, progressed?

JT: When they did their self-scouting at the end of 2013, they felt they lost up to 10 sacks where maybe [Chris] Long,[Robert] Quinn or both were rushing around the edge and the quarterback was able to step up in the pocket and just scrambled or buy a little time to complete the pass. But here with Donald, who is a classic three-technique interior pass rusher, they'll put him on rotation on passing downs and he'll shut that escape dash for quarterbacks. Donald, in OTAs and practice, has looked fantastic; not quite as impressive in the preseason games. Every once in a while he penetrated in the backfield and destroyed some stuff.

[Robinson] really struggled grasping the scheme and just struggled in pass protection. He's not going to start in the opener. They may work him in there a little bit, but Paul Boudreau, the offensive line coach, he's not afraid to kind of rotate offensive linemen as a whole in the regular season. So we may see a little bit of him, maybe not.

5. What do the Rams need to do to win the game?

JT: The Rams job No. 1 is obviously to stop [Adrian] Peterson and get [Matt] Cassel in 2nd and long, 3rd and long situations so they can unleash their pass rush. If Peterson's doing his thing and if it's 2nd and short, 3rd and short then the Vikings will have neutralized the Rams' best asset not only of their defense but of their team – the pass rush. The Rams are determined to stop Peterson, which is easier said than done. If they can just keep the lid on, I think they feel pretty good about their chances.