The Blaugrana boss maintains the Chilean is best suited out wide and insisted he has not held talks with the club about a possible contract renewal
The Chilean, 25, scored two tap-ins as the Catalans eased past Levante 5-1 on Wednesday and 9-2 in the Copa del Rey tie on aggregate, but his Argentine coach dismissed the possibility of him playing in the middle of attack in the future.
"This is usually a possibility," Martino responded to a reporter who pointed out the poacher's instincts showed by Alexis in his two goals. "I prefer central options such as Lionel Messi or Cesc Fabregas or even Sergi Roberto though.
"Alexis thrives more on the flanks. He plays with such intensity that it suits him and the team."
After the two-legged thrashing, Levante boss Joaquin Caparros said that Barca are stronger than Real Madrid and Atletio Madrid, but Martino refused to say his team are the best in La Liga's tight title race.
"I do not seek comparisons to them," he added. "Our problem with Real Madrid and Atletico Madrid is that we only have 90 minutes to play against either team in the league left this season.
"All three teams are fighting well and winning."
Martino also shot down suggestions that new Barca president Josep Maria Bartomeu had spoken to the former Newell's Old Boys boss about extending his contract at Camp Nou.
"No, the president has not talked to me about renewing," he added. "There's no truth that he has.
"I am very happy with the support that I have from them currently, I do not need a gesture from them at this point. I feel supported, they are satisfied with my work but we have not talked about a new deal."
Barca will face either Racing Santander or Real Sociedad in the semi-finals of the Copa del Rey, with a potential final against Real Madrid or Atletico to look forward to.