Silva will play a waiting game before determining if Gbamin – a player he believes “fits into my model" – can feature against Crystal Palace on the Premier League's opening day next Saturday.
“Jean-Philippe will improve our squad," said Silva.
“He's a good size, in good physical condition and is good on the ball, which is what I like.
“We need to give him time to adapt but he fits into my model, which is important.
“He didn't start for Mainz [in pre-season] because of the Africa Cup of Nations and didn't play for us today because he was at Finch Farm doing some work.
“We will take the decision on him next week."