The Rams have not produced a winning record since 2003, but there is more reason for optimism now than there has been in a long time. In back-to-back drafts, the Rams have invested in a franchise running back and quarterback. Even if things are trending upwards at those positions, though, the team may not have enough pieces in place for an immediate turnaround in its first season back in Los Angeles.

[More: Be sure to check out PFF’s ranking of all 32 NFL QB situations, offensive lines, running back units, receiving corps, secondaries, and defensive front-sevens. Catch up on all the team previews here.]

All eyes on first-overall pick Jared Goff

Quarterbacks: 27th in PFF’s season preview rankings

The Rams' low rank at the quarterback position is mostly due to how poorly QBs typically perform in their rookie season. More often than not, first-round quarterbacks end up with negative overall grades, even if they play well in later years. Based on everything we saw from Jared Goff at Cal, it looks like he could eventually be a star, but even current young, rising QBs like Cam Newton and Derek Carr earned negative overall grades in their freshmen NFL seasons. Outside of Goff, Case Keenum graded out as an average quarterback in his limited time. When he wasn’t under pressure, he produced an NFL passer rating of 102.2.

Todd Gurley has potential to become league's top running back

Running backs: Sixth

There are very few young star running backs currently in the league, but Todd Gurley is someone who falls into that category. He averaged 2.9 yards after contact per carry last season, which was second-most just behind Tampa Bay's Doug Martin. Gurley's 42 forced missed tackles while rushing were tied for fifth-most among running backs. Of his 1,106 yards, 508 came on his 16 carries of 15 or more yards. That is 45.9 percent of his rushing yardage coming on big runs, the highest rate in the league in 2015. If he can more consistently gain positive yardage, rather than just making a few big plays, he has the potential to become the top back in the NFL. In addition to Gurley, the Rams have Benny Cunningham, who is a good compliment on passing downs. Cunningham averaged 0.65 forced missed tackles per catch last season, the second best rate in the league.

Rams own NFL's worst receiving corps entering season

Receiving corps: 32nd

Last season, every team had at least one receiver with at least 700 yards—except the Rams. Over the last seven seasons, the only Rams receiver to top that mark was Kenny Britt in 2014, at 748. Their second receiver, Tavon Austin, averaged 9.1 yards per catch last season, the second-lowest mark for NFL WRs with at least 40 receptions. The team's third receiver, Brian Quick, recorded a 31.3 percent catch rate in 2015, the lowest mark in the league. Los Angeles added some intriguing players in the draft—Pharoh Cooper (South Carolina) and Mike Thomas (Southern Miss)—but it is very rare for a receiver drafted in the fourth round or later to make an immediate impact. At tight end, the Rams let go of long-time starter Jared Cook and brought in more mid- to late-round rookies. If their rookies are ready right away, then this group should end up higher come Week 17, but it's more likely that this unit will require more than one season to develop, and it will take time before the receiving corps can become a strength for the team.

Heavy O-line investment in recent drafts yet to pay off

Offensive line: 31st

The Rams have invested heavily in the offensive line in the past two drafts, though for the most part, things haven’t yet paid off. At left tackle, the Rams spent the second-overall pick of the 2014 draft on Greg Robinson, but last season, he allowed 21 combined sacks and hits, second-most for an NFL offensive linemen. Three of the Rams' six linemen with the most snaps last year were rookies, and only Rob Havenstein exceeded expectations—he was the only offensive tackle with at least 200 pass-blocks and no sacks allowed. Last year, Rodger Saffold was expected to lead the offensive line at right guard after three straight seasons of above-average grades, but he had a few bad games before landing on injured reserve. If Saffold returns to his old self and the young players start living up to their potential, then this offensive line looks a lot better.

Aaron Donald-led defensive line easily LA's strongest unit

Front-seven: Fourth

The clear strength of the Rams' roster is the defensive line. It’s a unit led by defensive tackle Aaron Donald, the best player in football last season. Defensive end William Hayes emerged from being a solid role-player to one of the better defensive ends in the league. His 11.7 pass-rushing productivity was sixth best for 4-3 defensive ends last season; he also led the position in run-stop percentage, at 11.5. Defensive end Robert Quinn only managed 349 snaps before ending the season on injured reserve, but he should be healthy to make the line even better than last year. Los Angeles lost backup defensive tackle Nick Fairley (Saints), but replaced him with Dominique Easley (Patriots), the only defensive tackle with a better pass-rushing productivity mark than Donald last year. The group of Alec Ogletree, Mark Barron, and Akeem Ayers are only an average trio of linebackers, but should be the best the Rams have had in years.

Key departures from secondary makes unit a potential liability

Secondary: 27th

The Rams' secondary was an asset for the team last season, as all four starters were solid players with no clear liabilities. The reason for the low rank here is that two of their three best players, Rodney McLeod (Eagles) and Janoris Jenkins (Giants) left in free agency. The only experienced safety option opposite T.J. McDonald now is Maurice Alexander. Despite just 434 career snaps all coming last year, Alexander allowed four touchdowns, tied for eighth-most among safeties. At cornerback, E.J. Gaines played well as a rookie starter in 2014, with 10 passes defended, but missed all of last year with injury. Either Lamarcus Joyner or free-agent addition Coty Sensabaugh will also see significant playing time, and neither one of them graded well last year. On the bright side, the unit should be helped with how good their front-seven is, but their secondary will likely prevent them from being one of the elite defenses in 2016.