Arsenal are hoping to sign the final piece which will complete the jigsaw puzzle of their midfield.

Martin Zubimendi, considered one of the world's best defensive midfielders, is set to join for £51m from Real Sociedad - a deal which has been widely expected since January.

The 26-year-old Spaniard rejected a move to Liverpool last summer and is now joining their title rivals a year later.

Zubimendi would most likely take the place of Thomas Partey - and link up with Declan Rice and Martin Odegaard in a midfield three.

So what type of player are Arsenal getting, and what will his role be at Emirates Stadium?

Zubimendi has played 236 times for Real Sociedad - his only club to date - and scored 10 goals.

But he is not a goalscorer, because he is primarily a defensive midfielder.

Real Sociedad played several formations last season, though mostly it was a 4-1-4-1 with Zubimendi as the pivot.

In La Liga in 2024-25, he ranked in the top five of central midfielders for successful passes, successful long passes, progressive passes, touches, tackles, interceptions, aerial duels won and distance of completed upfield passes (8.5km).

"His passing might sound simple, but he generally chooses well the one pass to do," said Spanish journalist Guillem Balague.

"He hardly ever loses the ball and that helps with fluidity and team confidence. He reads the game very well, without being the fastest midfielder - he has the puzzle of the team in his head.

"He is lately more up to driving with the ball and even getting into the box, and he would do that if he feels his team-mates can cover for him.

"But his main job is to help with build-up, sometimes going at the level of the centre-backs - make the game fluid, find the man with space, push the team forward, and do the same when it is the matter of applying pressure.

"He is very clever when it comes to deciding when to go or when not to go. A team player, a quiet leader. A key cog in the machine."

Zubimendi has won 19 Spain caps, and played nearly every game as the holding midfielder since Rodri's injury in the Euro 2024 final against England.

When Rodri - who would go on to win the Ballon d'Or - went off at half-time in that game, many observers felt that would be a boost for England.

But Zubimendi was impressive when he came on at half-time, with Spain not appearing to miss Rodri on their way to a 2-1 victory.

"I remember the reaction in the England fan and pundit camp when Rodri got injured in the Euro 2024 final," said Balague.

"I thought, 'hold on, it is Zubimendi coming on!' Spain have got two very good players in that position.

"I had a discussion with Thierry Henry about him. I put him in the top three in the world in that position - he convinced me to drop him to top five, but in any case he is very, very good."

Zubimendi is unfortunate that one of the few defensive midfielders ranked higher than him in the world is Manchester City's Rodri, with Spain only playing one player in that position.

But he made the most of his run in the team with Rodri out injured, including chipping in with some goals.

Zubimendi scored twice in the 2024-25 Nations League campaign, in the group against Denmark and the final defeat by Portugal.

In the Nations League knockout games in 2025, he ranked fifth for passes and successful passes, second for interceptions and seventh for tackles.

His form led to reports that Real Madrid, managed by Xabi Alonso, might try to hijack the move.

And the appeal could have been great with Alonso having come through the same youth team - Antiguoko - as Zubimendi, as well as also playing for Real Sociedad and Spain in the same number six position.

But Zubimendi is set on Arsenal, where he is likely to take the role of Partey - whose contract is expiring and future uncertain.

The Ghana international, 32, played 35 Premier League games for Arsenal last season - mostly in central midfield. Jorginho, who has left the club, started nine Premier League games.

While Partey drifts to the right side more for Arsenal (albeit including games at right-back), Zubimendi tended to go both ways - but more towards the left.

Rice played in the number six role for West Ham but usually appears further forward for Arsenal in a midfield three with Odegaard.

And Zubimendi's signing might free him up even more - with the Basque having better mobility than Partey, plus his focus on defending.

The Spaniard was more involved in his own half than Partey last season, with 56% of touches to Partey's 48%.

And only 27% of his passes ended up in the final third, compared with 32% of Partey's.

Arsenal will hope their summer spending is not finished yet, with a proper striker on the agenda - which could also affect how their midfielders play.