The Belgian global has scored a goal every 82 minutes for Manchester United, in comparison to a goal every 133 minutes when he was at Everton last season.
"He wants to play".
The 24-year-old is now on his own training regime away from the other players.
Lukaku has been a revelation since swapping Merseyside for Manchester in a stunning £75m deal earlier in the summer and has lifted United to second place on the league table, with only goals giving Manchester City the summit of the log.
"We'll take a decision on Friday".
"We have to be patient", Martinez was quoted as saying by Het Laatste Nieuws.
The Belgium boss said: "Romelu is working separately".
"For me, I see that it is a bit hard for him to be involved on Saturday, but we are still hopeful that he can be involved on Tuesday". "He hasn't trained with the group, he has a sore ankle and it is important he gets fully recovered".
Marouane Fellaini is also yet to train with his Belgium teammates this week because of the ankle problem he suffered in a challenge with Shane Long during United's 1-0 win over Southampton on September 23, although he is expected to recover before Saturday's game against Bosnia and Herzegovina.
News that he is not seriously hurt will be welcome by United, who face Liverpool on Oct 14.
The United striker has started the season like a train, failing to score in only one of his 12 appearances for club and country to date.
The in-form striker, who has netted 11 times in 10 games since joining the Red Devils for £75 million over the summer, is away on worldwide duty with Belgium.
Lukaku is the Premier League's top scorer this season with seven goals.