(Reuters) - West Ham United face a massive task to overturn their Europa League quarter-final first leg defeat by Bundesliga champions Bayer Leverkusen, but could be helped by the return of Jarrod Bowen, manager David Moyes said on Wednesday.

Bowen, top scorer for the Premier League side this season, missed the 2-0 loss in Germany along with the defeat by Fulham at the weekend with a knee injury, but has returned to training and is available for selection.