Mikel Arteta admitted Arsenal face a race against time to find a solution to their right-back dilemma.
The Gunners are on the verge of making this the most successful season in the club's history with just three matches remaining.
Two wins in the Premier League would secure the title and Arsenal then face Paris Saint-Germain in the Champions League final on May 30.
Arteta will be without Ben White for those games after his season was ended by a serious knee injury.
Jurrien Timber, meanwhile, has not played for two months and Arteta said only that the Dutchman had a "chance" of returning before the end of the season.
It leaves Arteta scrambling for a solution at right-back, particularly with Khvicha Kvaratskhelia looming on the horizon at left wing in the Champions League final.
Cristhian Mosquera is the favourite to get the nod if Timber does not return, though Arteta did shift Declan Rice to full-back against West Ham on Sunday.
There is also the left-field option of moving Riccardo Calafiori over to the other flank, as the Italian did for 45 minutes against PSG in the league phase of the Champions League last season.
That leaves Arteta with a big question and very little time to find an answer.
"I think the sample is so tiny, you know, so it's very difficult to judge a player when he had some low minutes," Arteta said when asked about Calafiori as an option.
"The same when we played Thomas Partey, we had some really good moments, some others when you don't win, and it's because Thomas plays as a full-back.
"Declan Rice, when he's played as a full-back against Brighton, he was exceptional. But then the other night, it was something else.
"It depends. The sample is still so little. It will remain so little from here to the end of the season to judge whether a player is good enough or can perform in the position."
Arteta also hinted that the team's struggles when Rice briefly shifted to right-back against West Ham would make him think twice about doing that again.
He continued: "And what is the cost of moving that player from one position to the other? And that's the balance that we need to try to find."
It had initially been hoped that Timber would miss only a few days with the groin injury he suffered in March but that has proved to be a more complicated issue than expected.
White had started to find some of his best form and was superb in the second leg against Atletico Madrid when Arsenal booked their place in the final.
Declan Rice, when he's played as a full-back against Brighton, he was exceptional. But then the other night, it was something else
His absence is therefore a huge blow but Arteta is confident that the team's experience of coping with injuries will stand them in good stead.
"We need to look at alternatives," Arteta said.
"The two players that we have there are not available at the moment. We need to look and do something else. The good thing is that we have experienced that all over the pitch this season.
"When we had issues, normally, they've been in the same positions as well. We have managed to find the right level of performance and consistency. I'm sure we will do that.
"There are different options in relation to the opponent as well and the things that we want to do. But we need to be open to that, not only to one but to two or three options.
"Games can vary, players can pick an injury. We need to be flexible on that and really think about that option."
