Ronald Koeman believes Gylfi Sigurdsson will help replace Romelu Lukaku as he explained why Everton are paying a club record £45 million (Dh213m) for the Iceland international.

Sigurdsson is set to complete a protracted move from Swansea City and the Everton manager sees the midfielder as a player who can compensate for the loss of striker Lukaku, who joined Manchester United for an initial £75m.

Lukaku was the Premier League’s second highest scorer last season while Sigurdsson ranked third for assists, with 13, while chipping in with nine goals himself, leading Koeman to declare him one of the best attacking midfielders in the division.

And Koeman said: “We worked a long time to get this deal and he was one of the key players to bring in. We knew we would lose Lukaku for this season and we need players who will bring quality to the team.”

Everton have already signed forwards Wayne Rooney, who scored on his second league debut for the club against Stoke City on Saturday, and Sandro Ramirez, but Koeman believes they have to spread the responsibility for ensuring Lukaku is not missed.

He said: “We lost 25 goals with Lukaku and we need more players than one to get that number of goals and he is that type of player with that productivity. He had really good seasons in Swansea. He is, in my opinion, one of the best in his position in the Premier League.”

Sigurdsson, who completed his medical on Wednesday, could make his debut against Manchester City on Monday, with Koeman saying that the 27-year-old Icelander, who was omitted from the Swansea side for their Premier League opener against Southampton, will not figure in Thursday’s Europa League qualifier against Hajduk Split.

“I have to talk to Gylfi and find what his physical state is,” the manager said.

While he has spent almost £150m this summer, Koeman reiterated that he wants to strengthen in two more positions, with another striker and a centre-back his targets.

Ramiro Funes Mori could miss the majority of the season with a knee injury leaving Koeman, who has been starting with three central defenders, short of cover at the back, while he had been linked with Arsenal forward Olivier Giroud in his quest to add a third forward.

Everton’s attempts to sell Ross Barkley, who is out of contract next summer and has rejected a new deal, have been complicated after the midfielder broke down in training.

“It looks like a hamstring injury but we need to do more tests,” said Koeman, who is not yet sure when Barkley will be fit.

Everton will definitely be without James McCarthy against the Croatian club, while Sandro is a doubt, but Koeman has pledged to name a strong side.

He will also be without Gareth Barry, who has joined West Bromwich Albion, with Koeman admitting he was reluctant to let the 36-year-old former England international go.

“It was really a difficult decision when Gareth asked to leave,” he said. “He knew maybe he wouldn’t play every weekend but I would have been really happy to keep him.”