The injury happened when Martinez collided with a Nashville player in the second half.
» MORE: Options for Atlanta without Josef Martinez
Martinez tried to continue until signalling to the bench less than a minute after coming back onto the pitch that he needed to be subbed.
Martinez is arguably the greatest striker in MLS history with 77 goals in 84 appearances. He was named league MVP in 2018 when Atlanta United won the MLS Cup.
Last season, in games in which Martinez appeared but didn’t score, Atlanta United went 5-3-1, and it went 1-3-1 when he didn’t appear.
Only one team in MLS was more dependent on one player to score than Atlanta United was on Martinez. Martinez scored 46.5% of the team’s 58 goals. Only Zlatan Ibrahimovic’s 30 out of 58, 51.7%, with the Los Angeles Galaxy was more.
Should Martinez be placed on the season-ending injury list, Atlanta United can replace him on the roster, according to MLS rules. If a player is placed on the season-ending list, the player can't return and play for the team that season in any competition. Martinez couldn't be replaced with another DP-level player because MLS rules state that the replacement player in that slot can't make more than $250,000. But that's only if Martinez is placed on the list. Atlanta United still has an open roster slot and international slot, president Darren Eales told an Atlanta radio station last week.
Martinez hasn’t before suffered a serious knee injury, according to transfermarktco.uk. The most serious injury he has sustained with Atlanta United was a hamstring injury in 2017.
The only other striker on Atlanta United's roster is Adam Jahn. While manager Frank de Boer praised Jahn, he also said after Saturday's game that should Martinez be expected to miss a significant amount of time that he would ask vice president Carlos Bocanegra to try to sign another striker.
Until then, or even if that happens, goalkeeper Brad Guzan said the rest of the players will have to step up.
“Our job is to one be ready and two to perform,” he said.