Currently, he is the most important player in Arsenal. Odegard is the bridge between the midfielders and the attackers. A perfect midfielder in the squad. If only they knew level of damage they has done to the Arsenal squad. Arteta will be grieving in pain by now. However, if I am in Arteta's position to fix a replacement for Odegard, I would prefer Trossard to fit in that position. The reason is because he is a very adaptable player, he controls both his right foot and his left foot. Someone in that position can possibly do what Odegard has been doing in the squad. Then Arteta should push Timber a little forward to fill in Declan Rice's space. And lastly Thomas Partey will hold firmly the midfield.
Honestly Odegard is a great players to Arsenal he always keeps his position very strong to avoid the linking up, because the kind attacks that is making during any of their matches is very good attacking; Arsenal can really miss the Odegard and that’s position will be link: Accept they put better squad in that position as replacements.
Arsenal start this season with so much good performances and with how they still so up their performances against any of their opponents they I have doubts that they might not face a much challenge like last season. Because Arteta knows what is right is always put much effort to make sure his teams did the best.