Argentina manager Jorge Sampaoli told Gonzalo Higuain his international career was not yet over on Friday, but said picking the right players to complement captain Lionel Messi was a challenge.
The twice World Cup winners belatedly qualified for next year's finals last month after a rocky campaign that sparked fears they could miss out on the tournament for the first time since 1970.
Higuain was a regular at international level for years but was dropped by former Chile and Sevilla coach Sampaoli for Argentina's crucial last four qualifiers.
Yet with no Argentine player other than Messi managing to get on the scoresheet in a competitive fixture this year, there is a clamour for Higuain, who has scored nine goals in 17 games for Juventus this season, to return.
Sampaoli said he had dropped the Juventus striker because "we established his presence was not ideal for him or the national team" but he then told him the door was still open.
"We have to watch him closely in the future," Sampaoli said.
Speaking ahead of a friendly against World Cup hosts Russia on Saturday, Sampaoli said he needed to bolster support for Barcelona great Messi.
"Finding ways to link up with Messi is going to be a determining factor for us," Sampaoli said. "We shouldn't wait for him always to provide the decisive moment."
Argentina's friendly against Russia will be the inaugural match at Moscow's newly-renovated Luzhniki stadium, the venue for the opening game and final of the World Cup.
Originally opened in 1956, Luzhniki was one of the venues for the 1980 Moscow Olympics. It hosted the 2013 world athletics championships before being closed for renovations to prepare it for the World Cup.
Argentina play Nigeria in the southern Russian city of Krasnodar, which will not host any World Cup matches next year, on Nov. 14.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)