The 26 year-old was replaced just after the hour mark in his nation's historic 3-2 victory over Mexico on Monday night, with what was described at the time as being a non-contact blow to his knee.
However, after further examinations and testing, the extent of the injury has now come to light, and at first viewing, it appears to be good news for everyone involved - none more so than Zack Steffen himself.
According to the information of injury analyst Ben Dinnery, Manchester City goalkeeper Zack Steffen had undergone tests to confirm that he has suffered a 'bone bruise' on his left knee.
This injury will now subsequently rule him out of the United States' exhibition game against Costa Rica.
After a year-long spell in German football, Steffen made the return to Manchester City, where he challenged Ederson for the number one spot during the 2020/2021 season - and during crucial moments in the campaign, was called upon.
The former Columbus Crew number one made notable appearances at the likes of Old Trafford to face Manchester United in the Carabao Cup, Stamford Bridge to face Chelsea in the Premier League during a Covid-19 hit period for the Etihad club, and even more memorably against Tottenham at Wembley in the Carabao Cup final.
Steffen will be looking to stake his claim even further next season, and with a similarly tight fixture schedule expected for Pep Guardiola's side, the USA number one is likely to see plenty of game time spread across multiple competitions.
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