The winger joined the Baggies last week on a season-long loan basis from Manchester City, where he had struggled to make an impact following his move from Swansea City in 2012.
However, despite the fact that he has had little game time over the last 12 months at the Etihad Stadium, Jones has insisted that the 24-year-old has shown positive signs since his arrival.
"We know what a good player Scott is and how well he's done in the Premier League. He's looked really sharp in training," Jones is quoted as saying by the Express & Star. "I'm sure we will see the best of him and he will improve the squad."
Sinclair has been tipped to make his debut against Newport County tonight.