Two right-backs in midfield - are Chelsea short despite £349m spent?

The primary issue is the absence of midfielder Moises Caicedo.

The Ecuador international is out with an unspecified injury for an unknown period after breaking down just 11 minutes into a substitute appearance against Brighton last week.

It has left Alonso in almost uncharted territory for a Chelsea boss. Aside from suspensions, Caicedo had missed only two matches during the previous three seasons, through a knock and illness.

Asked about Caicedo, Alonso said: "Not longer term, but it is about assessing the risk. Probably last week we brought him back too early and I don't want to make the same mistake again."

It remains unclear whether Chelsea had concerns over Caicedo's fitness while pursuing several central midfielders on transfer deadline day.

Monaco pulled the plug on Chelsea's £47m move for Lamine Camara at the last minute, leaving officials at Stamford Bridge furious.

Chelsea also had bids of up to £64m rejected for Bournemouth's Alex Scott earlier in the summer and were prevented from signing France international Manu Kone after Roma head coach Gian Piero Gasperini blocked the move.

Chelsea said they pursued Camara because of a market opportunity, adding that they were satisfied with their summer business and retained faith in their current options.

That was despite selling Enzo Fernandez to Manchester City for a joint British-record fee of £125m on deadline day, without signing a direct replacement.

However, Caicedo's absence means he joins Jordan Henderson on the sidelines, with the England international still recovering from a broken arm suffered after falling over an advertising hoarding while an unused substitute at the World Cup.

Natural midfielder Valentin Barco, who joined from Strasbourg in the summer, has been overlooked in favour of Gusto in all three of Chelsea's Premier League matches.

With Gusto starting in midfield, Chelsea recorded 25.6% possession in last weekend's 4-3 victory over Brighton, their lowest figure since records began in 2003-04.

If all of Chelsea's midfield options are fit, and Caicedo's injury proves only minor, they should be able to cope with five midfielders in a season without midweek European football, as Alonso argued before the match.

Chelsea have leaned on their star attackers in Morgan Rogers, a resurgent Cole Palmer and the prolific Joao Pedro in their opening three matches.

Yet having conceded seven goals in three matches, Alonso said "we want to be tighter".