LONDON -- Arsene Wenger has acknowledged that Theo Walcott hasn't developed "as well as you could have expected" this season, but still believes the former teenage sensation will prove himself as a central striker.

Walcott celebrated his 10-year anniversary at the club in January after joining from Southampton as a 16-year-old. But the club's longest-serving player remains far from fulfilling the promise of his talent, and he has fallen behind the likes of Danny Welbeck, Olivier Giroud and new starlet Alex Iwobi in the pecking order.

After starting the season as Wenger's first-choice centre-forward, Walcott has had to settle for a place on the bench lately and is in danger of being overlooked by England coach Roy Hodgson for this summer's European Championship.

And Wenger agreed that the vision of Walcott blossoming into a top-class central striker this season hasn't really come to pass.

"Not as well as you could have expected," Wenger said ahead of Saturday's Premier League visit to London rival West Ham. "He had good periods in the season. I think recently he has gone through a much more difficult period. But he will come back."

Hodgson has said Walcott needs to win back a starting spot at Arsenal to earn a place at the Euros, but that looks unlikely given the recent emergence of Iwobi on the wing and the strong displays from the fit-again Welbeck up front. However, Wenger said Walcott looks determined to do so.

Theo Walcott finds himself behind Alex Iwobi and Danny Welbeck in the Arsenal pecking order. BEN STANSALL/AFP/Getty Images

"He works very hard, he puts the effort in in training. At the moment, for him and Giroud it's a bit more difficult, but that's part of the competition," Wenger said. "He understands that as well, and he fights very hard. But in our job things can change quickly from one week to the next."

The question also remains whether Walcott is best suited in the center of Arsenal's attack or on the right flank, where he spent most of his career. Wenger said even the forward seems to struggle to make up his mind when he's on the pitch.

"The problem with Theo is he wants to play on the right and through the middle. You have to fix yourself somewhere. When he does go through the middle he thinks maybe it's better for me on the right," Wenger said.

"It's true that I fixed him more through the middle, because of the quality of his runs and the intelligence of his runs. And he has improved his finishing a lot, so he can be a player through the middle. On the flanks today you have to work very hard defensively."