West Brom coach Peter Grant says the tailing off of Gianni Zuiverloon's season is due to his Beijing Olympics commitments.
"It's been a long season for Gianni," the former Norwich boss told the WBA website.
"He played in the Olympics during the summer, didn't have a proper break and this is his first season in the Premier League.
"The position he plays is a very, very difficult one. People used to call it the graveyard shift because you're always running up and down the full length of the pitch.
"We're constantly on his case because, at the start of the season, he was doing that. But he was in full flow then. He'd just come back from the Olympics and his fitness levels were probably higher than everybody else's.
"But that can have the opposite effect at the end of the season.