The 31-year-old was a surprise £27M signing for Julen Lopetegui’s team, arriving from Borussia Dortmund.
However, he has yet to score a goal and has only managed 63 minutes of Premier League action.
“I had a really bad start,” Fullkrug recently told DeichStube.
“I moved to London to West Ham after a very short summer break and after an intensive year last season, I think I played 57 games last season. And then a short break in which I felt that I had recovered relatively well.
“But then I had a rocket start because I moved here a week and a half before the start of the Premier League season and had a few sessions at BVB.
“I’m working very hard for it. I’m undergoing treatment and I’m getting good support at West Ham and I just hope that I’ll get fit again as soon as possible and can finally play in the Premier League on a permanent basis and show what I’m capable of there too.”