If Arsenal had to pick a player to play the whole season injury free, then Bukayo Saka would be first or second on that list.
Mikel Arteta was previously fortunate that one of his key players has been away from the sidelines for so many years.
Over the past three seasons, Saka has missed just 10 out of Arsenal's 172 matches in all competitions - and since making his Premier League debut six seasons ago, he has never been out for more than one top-flight game at a time due to injury.
Arsenal are rarely without Saka but now they are on foreign ground given he is now sidelined for "many weeks" due to a hamstring injury sustained at Crystal Palace.
It is a huge blow because of Arsenal's dependency on the England winger. Firstly, his end product is unrivalled at Arsenal and only a handful of Premier League players have a better influence over their team in terms of goals and assists.
But crucially, Saka is a key cog in Arsenal's game plan. Out of all Arsenal's front three players in the last four seasons, Saka has more minutes than the next two most ever-present forwards combined.
Not only is he one of Arsenal's key corner takers alongside Declan Rice - with the Gunners the outright dead ball experts across Europe - but the manner in which Arteta's side come forward regularly involves Saka.
Nearly 50 per cent of Arsenal's attacks going forward go through Saka territory - and that number has been increasing every year. This season's 46 per cent leniency towards the right wing is the highest dependency out of any Premier League team.
"He's a massive player for us," Arteta said on Monday. "You have to see the impact he has on this team but it will be a good exercise for all of us to overcome another challenge, because we've had a lot in the season.
"I'm putting some ideas together, I haven't got there yet. But I have a few and then I want to speak with them to understand how we're going to generate that and take it in a positive way. That is going to mean we're going to be different."
Arsenal lost Martin Odegaard to a six-week injury earlier this season and Arteta did not claim his team have to change their ways. But with Saka, it's a different story - especially with back-up right winger Raheem Sterling also set for weeks on the sidelines with a training ground injury. So what could Arsenal's game plan look like now?
The most likely to step in on the right flank for now is Gabriel Martinelli, who was the immediate replacement for Saka down the right wing in the 5-1 victory over Palace.
The Brazilian winger swapped flanks from left to right and ended the game with a goal and an assist to his name. Greater challenges than Palace will test that, but it is worth noting that Martinelli also started on the right wing when Arsenal beat Everton on the final day of last season.
Martinelli shares the same attacking verve Saka has in terms of wide play, with the 23-year-old second to the Englishman in the list of most Premier League one-on-ones in the last two and a half seasons.
However, the vast, vast majority of those plays have come from the left wing - to the point where only 4.5 per cent of his Premier League minutes for Arsenal have come from the right flank.
Another player who has deputised for Saka down that wing is Gabriel Jesus - who started Arsenal's 1-0 win over Manchester City last October when the England winger missed the game with a knock.
But, albeit over the last week or so, Jesus has been in good form at centre forward for Arsenal, with five goals in his last two games. Does Arteta weaken another position to fill the Saka hole?
The issue that both Martinelli and Jesus have is they are right-footed. It is a different option to Saka, whose left-footed threat combined well with the same-footed Odegaard.
Arteta recognised that in his press conference on Monday: "We're going to have the options to play both footed as well. If we need to, another kind of profile in relation to the opposition. So, we are on it."
So is the left-footed Kai Havertz set for the right wing?
Arteta revealed on Monday that he wanted to speak to a wide pool of players about how this "different" Arsenal could look - one of the options was asking the left-footed Havertz to do "different things".
It would be a bold move, given Havertz has only ever played as either a centre forward or an attacking midfielder since joining from Chelsea 18 months ago, while his duel-winning ability would also be redundant out wide.
Arteta namechecked Leandro Trossard as well in terms of a contender for the right wing position. The Belgian has a reputation of being two-footed which would suit Arteta's criteria for the role but like Martinelli, is more suited to the left flank.
There are also doubts over Trossard's abilities as a starter - given his form for Arsenal has been much better as a 'super sub'. The Belgian has failed to nail down a starting spot on the left wing and has just one goal from five starts down that flank.
But Arteta may have no choice but to start Trossard, especially if Martinelli is needed as a right winger in the coming weeks.
So with cons partnering the pros in terms of the internal candidates to replace Saka, does that give Arsenal a reason to dip into the transfer market?
Before Saka's injury, the Gunners had a relaxed view on the upcoming January transfer window - they would only enter the market if a summer transfer target became available early, or if injuries forced their hand.
With Sterling also out injured, injuries have set Arsenal back on the right wing. But Arteta admitted this week they were more preparing for a potential defender signing - with Ben White and Takehiro Tomiyasu suffering long-term injuries this season - rather than further forward.
"If something has to happen, we will be open to it," said Arteta. "But the main focus is now how do we have the structure still with the potential in this squad?"
Arsenal have had a mixed relationship with the January window under Arteta. In Odegaard, Trossard and Jorginho, they have occasionally moved for targets - but last summer saw them stick with what they had - and they were within two points of the title.
With options such as Marcus Rashford on the market, it may be tempting. But history may say Arteta will rely on cover already at the club - ahead of a crucial time in the season.