Sonko, 26, who has finally been given the go-ahead for his comeback after an operation in February to reconstruct ruptured cruciate knee ligaments, has already played in three private friendly matches and two reserve games in the last few weeks.
And Reading manager Steve Coppell believes the Senegal-born centre-back is now on the verge of a first-team return, saying: "These games are really proving to be valuable for us and will be to our advantage."
Coppell told the Reading Evening Post: "He (Sonko) will be very much in contention for the first-team squad in the next week. Once he has played four or five games we will know he is almost there.
"And he will have an impact when he comes back. He will bring a mentality which unites us all. He knows he has also got a lot to prove at Premier League level."