Anterior cruciate ligament injuries usually require at least three months to heal, which means that not only is Lanzini going to miss the showpiece event in Russian Federation, but he is also expected to be on the sidelines when West Ham begin their new season.
If Lanzini is indeed ruled out then it is nearly certain that Icardi will finally get the chance of representing his nation in the 2018 Fifa World Cup in Russian Federation.
Argentina are in Group D at Russian Federation 2018, beginning their campaign against Iceland on June 16.
No survivors after small plane crashes in Kenya
The CS208 plane, registration number 5Y-CAC, was flying from a Kitale airstrip in Trans-Nzoia County to Jomo Kenyatta International Airport when it lost contact with control tower at 5pm.
An 85th-minute goal in a friendly meeting with Italy back in March appeared to have helped cement his place in Argentina's World Cup squad.
Argentina have a wealth of attacking options to choose from, with names such as Sergio Aguero, Gonzalo Higuain, Paulo Dybala, and, of course, Lionel Messi making other national teams a different shade of scarlet with envy.
Inter Milan captain and striker Mauro Icardi is expected to be called up as Lanzini's replacement.
West Ham fans took to Twitter to express their disappointment at the news and with their superstar well in his recovery from a nasty injury.