Signed from Borussia Dortmund in 2018, the Ukrainian's flashes of brilliance have fizzled out into minutes for the Hammers' U23s.
Making an appearance in the Premier League Cup against Swansea's youth side, Yarmolenko scored the game's eventual winner in first-half stoppage time, but didn't even bother to celebrate.
His lack of enthusiasm was then justified at the start of the second 45 when the most innocuous of elbows resulted in a bizarre red card.
Backing into Swansea's Ben Erickson, Yarmolenko used his arms to hold back the defender from a throw-in, but barely made contact with his opponent.
The referee had no doubt at all about what looked like a very doubtful sending off, with Yarmolenko only able to laugh as he walked off the pitch shaking his head.
Former West Ham defender Kenny Brown perfectly summed up the mood, saying: "It's disappointing, the referee couldn't wait to get his card out."
Yarmolenko may take some solace in the fact his headed goal won the match, but that will do little to distract from a West Ham career that is very clearly coming to an end.
The winger has only started eight games in all competitions this season, scoring once in his 21 appearances.
Yarmolenko's time at the London Stadium looks certain to come to an end when his contract expires this summer, and he'll certainly be hoping for one last hurrah with the first team to avoid bowing out on the strangest of lows.