Pierre-Emerick Aubameyang Unai Emery's main man, Lucas Torreira also crucial at Arsenal

Last September, we looked at the most important players at Arsenal. With the new season underway, who are the risers and fallers?

This list is not extensive and has been ranked according to varying factors. Some players still with a part to play have been omitted.

Performance, potential, the ability to make an impact and influence the course of a game, other options in that area of the field, the ability or inability to replace them and market value have all played a part in revising the 15.

1. Pierre-Emerick Aubameyang (new entry)

Arsenal haven't had a world class centre-forward since Robin Van Persie left for Manchester United in 2012 but Aubameyang finally gives them a player capable of competing for the Premier League's golden boot award. After arriving in January, the Gabon international should be able to hit the ground running in his first full season in England. The Gunners better hope he does -- they probably need a 30-goal campaign from the forward in order to compete for a top-four finish.

2. Mesut Ozil (+1)

One of Unai Emery's biggest tasks will be to figure out how to make the most of Ozil, who isn't naturally suited for the Spaniard's high-pressing style of play. And he seemed wasted at times in the 4-3-3 system Emery deployed against Manchester City in the season opener. But Ozil is still the most talented and highest paid player in this squad and the natural focal point of the team's attack. The German doesn't come off as a natural leader, but as one of Emery's five captains he must now shoulder increased responsibilities on and off the pitch.

3. Lucas Torreira (new entry)

It might be asking a lot of the newcomer, but Torreira seems to be Arsenal's best hope of finally finding some defensive balance in the team. The Uruguayan plugs a major hole in the squad, which was without a natural holding midfielder, and could be the key to making Emery's pressing tactics work. Arsenal haven't really strengthened the back four much in the summer, so any defensive improvement could be down to Torreira's ability to shield his defenders and provide a ball-winning presence in midfield.

4. Aaron Ramsey (+3)

Ramsey has yet to commit his long-term future to the club but Emery has made it clear he views the Welshman as a key figure in his set-up. The midfielder showed glimpses of his 2013-14 form last season but will need a full return to his best in order for this Gunners side to really click.

5. Petr Cech (no change) / Bernd Leno (new entry)

While Cech started ahead of Leno against City, we still don't know who will be the No. 1 goalkeeper going forward. But whoever Emery picks will need to take on the added responsibility of being an outlet in the passing game, with the Spaniard determined to have the goalkeeper play the ball out of the back. Leno seems the more natural choice for that task, although Cech may still be the better goalkeeper overall.

6. Alexandre Lacazette (-4)

Lacazette may be in and out of Arsenal's starting lineup this season depending on what kind of formation Emery chooses, but the Frenchman still has a massive role to play. Aubameyang can't shoulder the scoring burden alone, and Lacazette provides the team with a double threat going forward. He has also shown a great connection with his strike partner, and the duo provides Emery with a lot of tactical flexibility that will keep opponents on their toes.

7. Sokratis Papastathopoulos (new entry)

Sokratis has the unenviable task of shoring up Arsenal's leaky back four, and it's hard to see how he's going to do that on his own. But his leadership qualities are sorely needed and he's more vocal on the pitch than the injured Laurent Koscielny, which could help make the defence more organised.

8. Shkodran Mustafi (+3)

Arsenal's fate may depend in part on whether Emery can turn Mustafi into a player who was worth his price tag. The German has been too inconsistent and prone to mistakes since joining for £35 million two years ago, and will need to improve massively for Arsenal's defence to become respectable.

9. Hector Bellerin (no change)

Speaking of defenders improving, there are high hopes that Bellerin's development will benefit from more hands-on coaching under Emery. The Spanish right-back is a great attacking outlet but he still has a lot to learn about the art of defending. Arsenal need him to take a big step forward in that department this season.

10. Henrikh Mkhitaryan (new entry)

Like Ozil, Mkhitaryan looked out of place in Emery's 4-3-3 formation and it's still a bit unclear how to make the best use of him in this side. But the Armenian playmaker is still a top asset if used properly, and his connection with Aubameyang from their Borussia Dortmund days could prove invaluable.

11. Nacho Monreal (+1)

With Sead Kolasinac out with a long-term injury, Monreal is Arsenal's only real option at left-back. Fortunately, he's been one of the club's most consistent performers in recent years, and there's no reason to think his level will drop this season.

12. Granit Xhaka (-6)

Xhaka remains a bit of an enigma at Arsenal -- a very good player who just doesn't seem a very good fit in this team. With Torreira taking over defensive duties, Xhaka could be freed up to take on more of an attacking role if Emery sticks with a three-man midfield. However, he could also be sacrificed in favour of a 4-2-3-1, with Ramsey probably ahead of him in the pecking order.

13. Stephan Lichtsteiner (new entry)

Lichtsteiner is unlikely take over Bellerin's starting role, but he could still have a big impact as a teacher and mentor -- not to mention as a valuable backup. If the 34-year-old veteran is able to impart his knowledge and experience on Bellerin, that alone would be a massive benefit.

14. Matteo Guendouzi (new entry)

The 19-year-old midfielder was billed as a signing for the future when he joined this summer, but the Frenchman was thrown straight into the hotseat as a starter against City. He may lose that spot when Torreira is ready to start, but the teenager provides Emery with one more central midfield option.

15. Laurent Koscielny (-11)

The club captain would be much higher on this list were it not for the torn ACL that will sideline for him at least half the season. But if he gets back to his top form quickly and hasn't lost a step when he returns, he should still be the best centre-back in the squad.