An injury crisis has hit Xavi's squad during the international break, with Jules Kounde and Ronald Araujo having incurred problems.
Kounde is set to miss three weeks of action whilst Araujo could be on the sidelines for around two months.
It has come at a difficult time for Barcelona with important games against Mallorca, Inter Milan, and Celta Vigo on the horizon.
Therefore, De Jong and Alonso may fill in for the injured duo as Xavi has to tinker with his squad.
De Jong has previously played at centre-back for Ajax under Erik ten Hag before arriving at the Nou Camp.
The Dutch midfielder has also played under former Barcelona manager Ronald Koeman for the Netherlands in the role as well as being trialed in the role by Xavi during pre-season.
Alonso's versatility was a reason behind his signing and the Spaniard has played in centre-back for former side Chelsea in the past.
This may just be a last resort as Barca do boast the likes of Eric Garcia, Andreas Christensen and Gerard Pique as centre-back options.
Kounde may return for the huge encounter with Real Madrid in El Clasico on October 16.
However, Araujo may not make another appearance for the Blaugrana before the 2022 FIFA World Cup kicks off in late November.
Barcelona will look to continue their impressive start to season
The absences of Kounde and Araujo come as a blow for Xavi's side but the Spanish tactician now has real strength in depth off the back of a huge summer transfer window.
Barcelona have made a brilliant start to the new season and currently sit second in the La Liga table with five wins and one draw in their six league fixtures thus far.
Next up for the Blaugrana is a trip to Mallorca where they will be looking to continue their red-hot form.
Robert Lewandowski has flourished with 11 goals in just eight appearances since his £40.5 million move from Bayern Munich this past summer.
The likes of Raphinha, Ousmane Dembele, Gavi and Pedri are aiding the Pole in his remarkable goalscoring form.
All eyes are on the upcoming El Clasico and how Barcelona will fare against the reigning La Liga champions.
A win over Carlo Ancelotti's side would be a huge statement of intent for Xavi's men.