Jimenez, 29, joined Wolves in 2018 on loan from Benfica before making his switch permanent the following April.
The Mexico international scored 13 Premier League goals during his first season in England, and has improved on that this term with 15 - and 24 in all competitions - to earn transfer interest from some of Europe's top clubs.
United and Juventus have both been linked with the forward, and Jimenez's national coach believes Old Trafford would be a better move given the amount of competition for starting roles in Turin.
"Looking at it from the outside today I cannot see a specialist No. 9 like Raul at United," Martino told ESPN's Futbol Picante.
"There are many forwards like [Marcus] Rashford, [Anthony] Martial and the boy who now plays as right winger: [Mason] Greenwood but since Romelu Lukaku left I can't see a pure number nine like Raul.
"At Juventus he will have more of a fight because [Cristiano] Ronaldo shares the inside of the pitch with whoever plays alongside him, with [Paulo] Dybala or with [Gonzalo] Higuain and maybe he has a tougher fight there."
United currently have Odion Ighalo on loan until the end of January 2021, while Ole Gunnar Solskjaer's priority signing remains Borussia Dortmund winger Jadon Sancho.
But Martino continued: "We who see it from the outside, you [the journalist] and even me, always have the idea that a player has to aim for more and how good it would be for him to go to play for Manchester United.
"For me, that at one point in my life I was in a very big club [Barcelona], and having lived a difficult year there, I say that you have to be convinced of the step you want to take and you have to analyse it from many places.
"And he has elements to analyse it because, although he has not been at Manchester United, he was at Atletico Madrid and he was at Benfica. And he has elements to put in the balance to decide what he wants from his life.
"Maybe he wants a bigger challenge because he feels that he is in good shape and has to take advantage of it, maybe he wants to stay in this place, maybe the options you read about are not real and do not exist.
"I think the best thing is for Raul to make the decision based on the analysis he makes and with the consensus of his family because, when it comes to enjoying, not only the player suffers and enjoy, but also the family do it."