Manager Brendan Rodgers was backed in the summer following his return to the club and recruited 10 new players, including wingers Luis Palma, Yang Hyun-jun and Marco Tillo.
While Palma and Yang have both settled into life in Glasgow and have featured regularly for Celtic this season, Tillo made his debut for the club in a 1-1 draw with Motherwell last weekend following a lengthy spell on the sidelines.
Celtic are currently having to cope without attacking duo Liel Abada and Daizen Maeda due to injury, and Rodgers is believed to be keen to further strengthen his options in the final third in the New Year.
According to The Telegraph, Celtic have identified Portuguese wideman Araujo as a January target and hope to strike a deal with Estoril worth in the region of £4m.
The 22-year-old is said to be the subject of enquiries from Celtic, who have been keeping tabs on his performances at Estoril since he joined from Benfica 18 months ago.
Araujo began his career in Benfica's academy, but failed to make a senior appearance for the Portuguese giants and was loaned out to Arouca for the 2021-22 campaign, featuring 16 times.
The Portugal Under-21 international has since become a first-team regular with Estoril and made 30 appearances last season before featuring 16 times in all competitions this season, chipping in with two goals and three assists.
Araujo has predominantly played in a deeper wide role this term as either a left-back or left midfielder, starting all 11 games in the Primeira Liga as well as five outings across the Taca da Portugal and Allianz Cup.
The versatility of Araujo is believed to appeal to Rodgers as he attempts to shape his squad into one that can eventually compete at a high standard in both domestic and European competitions.
Celtic currently sit top of the table, eight points clear of their nearest challengers Rangers in second, but they are on the cusp of elimination in the Champions League group stage as they sit rock bottom of Group E with just one point from four matches.
They will look to keep their slim hopes of reaching the Champions League knockout rounds alive when they face Lazio in Italy in their penultimate Group E fixture on Tuesday.