Arsenal are top of the WSL, yet still in need of reinforcements. Joe Montemurro’s side face third-placed Chelsea at a sold-out Meadow Park on Sunday in one of the most eagerly awaited games of the season and the manager knows that, long term, their squad is not big enough. This weekend, however, he will have to rely on the players already in the squad.

The Australia international forward Caitlin Foord is a player who has been “of interest for a while” and there are others too but so far this transfer window there have been only departures. Emma Mitchell has joined Tottenham on loan, Tabea Kemme has retired and forward Danielle Carter is a long-term absentee.

On Sunday they face a squad that is significantly larger than theirs and at some point during this season that could well have an impact on the title race. Chelsea’s Emma Hayes has 23 players in her squad. Arsenal have 18, and without Carter it is 17: 11 players, six substitutes and no margin for error.

Yet their injuries, while not rocking the core of the team as they did last season, go beyond Carter. Midfielder Katrine Veje has still not returned from a temperamental foot injury that has meant she has not seen a minute of action this season. Defender Jen Beattie, who rejoined the club from Manchester City in the summer, has not played since the team’s 9-0 defeat of London Bees on 11 December.

Montemurro said this week: “They’re ready to go but we just felt we’d maybe give them another one or two games to get them 100% right. We’ll go from there. We are trying to rotate and look at load management, not just for this week but an accumulation going into February and March. The beauty of the squad we’ve got is that whatever starting XI we put out there, we believe that it’s going to be very competitive and represent the club in the right way.”

Increasingly, the head coach is having to look to the academy to help bolster his bench with 17-year-olds Melissa Filis and Ruby Grant already having been selected for matchday squads in the past two seasons – including the Gunners’ 2-1 defeat to Chelsea in October.

Blooding youth and letting them know how close they are to taking the step up is important and is how Montemurro likes to work; with a small squad where players constantly feel like they have a chance. However, even with their own injury problems, Chelsea will not have a 17-year-old on the bench, perhaps bar young goalkeeper Emily Orman; instead they will have a host of top internationals to call upon.

There were other issues in the Gunners’ loss at Kingsmeadow three months ago. “We have to continue at our rhythm, at our tempo, at our style for 90 minutes,” said Montemurro, pointing to where they went wrong. “We can’t afford to drop it. They’re a team that are very quick in transition and are very direct. We lost our way a little bit in the second half and we just need continuity. I’m sure that we’ll be competitive and make sure we get the best we can out of the game.”

Without fresh and experienced legs off the bench though, it is easy to dip. In October’s game, Arsenal made one change, bringing on the still-rusty midfielder Jordan Nobbs for Lia Wälti. Hayes, meanwhile, put on defender Maria Thorisdottir and forward Ramona Bachmann with 15 minutes to play and the latter set up the former for the winner.

Should Chelsea win on Sunday, they will close to within a point of Arsenal with a game in hand and their deeper squad could again be a deciding factor.

Montemurro is skating close to the edge. When asked where the game will be decided he said: “I can only comment on us. We’re a team that wants the ball and wants to keep the ball and when we have the opportunity to get comfortable and play the way we want to play, I’m sure we’ll find the spaces to exploit them.”

Added to Chelsea’s ranks since that game in October is the forward voted No 1 on the Guardian’s top 100 female footballers list, Sam Kerr. Montemurro refuses to be drawn on the impact of his fellow Australian. “It’s not for me to comment about other teams and what they do and how they do it, but the reality is that Chelsea have a number of very, very good players and obviously Sam Kerr is a component of that.

“We go into the game worrying about ourselves, so that’s why I don’t feel scared about who we play. We worry about how we’re going to play, and how we’re going to command and dictate the game. I don’t look at individual players or individual scenarios, we just look at making sure we play the way we want to play.” Having a few more players that help them do that though would surely make Arsenal fans sleep a little easier.