​Manchester United kick off their Premier League campaign away to Hull City this weekend, and there is plenty of optimism around Old Trafford as the new season begins. The arrival of Michael Carrick brought a positive end to last season, with United impressing at times as they finished third in the Premier League and secured a place in the Champions League. United are expected to secure Champions League football at the very least this season (Getty)Many will be now expecting Carrick to build on last season’s success. While the club is aiming to return to regular Champions League football, the longer-term goal is to build a team that is capable of fighting for the Premier League. They have taken steps towards that already this summer. The arrivals of Youri Tielemans and Andrey Santos kickstarted the midfield rebuild, but there are still some noticeable gaps in the squad to fill. But with just over a week left of the summer window, time is running out to add quality in key areas. So, what does the club need before the window shuts? The business so far To begin with, it is worth considering that there are two areas that are no longer in need of immediate improvement. Goalkeeper is one, with Senne Lammens having impressed since arriving last summer. While the Belgian may not yet have proved himself to be at the level required to win major honours, he is certainly good enough for now, and could well move up a level in the coming seasons (though a competent back-up could be on the list soon enough). Tielemans and Santos have arrived from Aston Villa and Chelsea to bolster the midfield, but the squad definitely needs one more starter in midfield. The club remain linked with Brighton’s Carlos Baleba. A bid of £60m has been tabled for the Cameroon international, and it is expected that a deal will be reached before the end of the transfer window. The signing of Baleba would mark the arrival of a player the club had originally targeted last summer, and some will regard the 22-year-old as the final piece in an impressive midfield rebuild. Having only lost Casemiro this summer, the club have seemingly filled the gaps in the middle of the park, with Kobbie Mainoo, Bruno Fernandes and Mason Mount the other options. While we are yet to see if the midfield works in practice, it is looking much better on paper than it did last season. Youri Tielemans is the most high-profile signing that United have made so far (Getty)Carlos Baleba looks set to become the third midfield signing this summer (Getty)Position one: Centre-backThe only real area of concern at the moment is in defence. United currently have nine first-team defenders on the books, with arguably only one of them currently possessing the quality needed to be part of a league-winning side. Matthijs de Ligt is the man in question, though he has only just returned to training after an injury suffered in November, and his injury record could see him forced out of the club in the longer term. Hopes are hi