In defence, the popular choice is Southampton’s Virgil van Dijk.

The Dutch defender is back playing football again after his exile in the summer, and although the Saints fought hard to keep him, an exit in January remains a strong possibility.

Anything north of £50m may be enough to convince Southampton to sell.

Arsenal’s need for a defender is down to a number of factors.

One is the pending retirement of Per Mertesacker, who Arsenal will certainly have to replace if they want to keep their options strong. Another is the fading form and fitness of Laurent Koscielny.

On his day, the Frenchman is still one of the Premier League’s best defenders, but there are only so many games he can play before he needs rest. Then there is Shkodran Mustafi, who has the makings of a good defender but has yet to find the consistency a title challenging team needs.

Van Dijk would add height and aerial dominance to the Arsenal defence, while also being no slouch on the ground. Perhaps his most impressive trait is his ability on the ball.

It was this quality that had managers such as Jurgen Klopp and Pep Guardiola so keen on him, and something that Arsenal’s backline could use given their recent mistakes when passing out from the back.

With a high asking price and plenty of competition for his signature, signing him wouldn’t be easy, but the extra effort could be more than worth it.

In midfield, there’s Sevilla’s Steven N’Zonzi.

The 29-year-old has been out in the cold at Sevilla since their 3-3 draw with Liverpool in November after a falling out with their head coach, Eduardo Berizzo.

He recently spoke of his desire to leave the club, and has a release clause of £35m.

For someone who would be a very good midfielder in the Premier League, that’s excellent value in the current market.

N’Zonzi has improved tremendously during his time in Spain.

He possesses a blend of height, strength, mobility and technical quality that makes him such an imposing figure in midfield. While Arsenal have no shortage of good passers, few have the defensive ability that N’Zonzi has.

He’ll rarely play long, pinpoint forty yard passes to a centre forward, but he’ll rarely misplace a simple five yard pass, either.

With these skills, he’s a definite improvement on Francis Coquelin, who is a good ball winner but lacks the discipline and technical quality of a top class holding midfielder, and Mohamed Elneny, who uses the ball sensibly but lacks presence in defence.

He is of a different mould to Granit Xhaka – less creative on the ball, but a more reliable defender – which means he could partner the Swiss as well as deputise for him.

His Blackburn and Stoke roots make him unfashionable, but he would improve Arsenal’s midfield in several areas.

Finally, in attack, Arsenal must look at signing Lyon’s Nabil Fekir.

For a possible price of £45m, Arsenal could get a player who could replace Alexis Sanchez and form a formidable partnership with Alexandre Lacazette.

Fekir has been a star for Lyon this season and has become more productive in front of goal. On top of his goal getting, the 24-year-old also has a touch of class about him.

He’s a tricky dribbler who can produce outstanding moments of individual quality, whether that be creating a chance for someone or scoring a goal out of nothing.

Losing Alexis would mean losing a lot of spontaneity from Arsenal’s attack, but Fekir has that spades.

In addition, he has versatility. His best role is behind the striker, but he can play on the flank or up front as a striker.

Even if he doesn’t reach Alexis’ level, there’s still merit to signing someone who has a bit more about him than Danny Welbeck and Alex Iwobi do. Both players struggle for consistent end product, while Fekir is only becoming more consistent in the final third.

Few attackers in Europe at the moment come as ready made as the Frenchman.

Signing all three players in the January transfer window might be asking too much of Arsenal, but just bringing one of them in would really improve the squad.

Arsenal aren’t going to be winning the title this season, but nothing says they can’t start putting the pieces in place for next…