Obi-Martin, who joined from Arsenal’s academy last summer, has impressed with nine goals in 11 appearances for United’s youth sides.
With the club’s attacking options depleted after several loan departures and current strikers Rasmus Hojlund and Joshua Zirkzee struggling for goals, Amorim may turn to the talented youngster.
"He’s doing his job," Amorim told his news conference about Obi-Martin.
"He’s improving, he’s playing in the youth teams, and also we have other players who can play that position.
"Rasmus and Josh are there. We bought these two players, we need to improve them, and sometimes the confidence can change a player. We will see in the end of the season.
"But until then we have two strikers who can score goals, they’ve proved in the past, so let’s see if we can improve as a team to help them to score goals."