However, Hakim Ziyech is in line to make his first appearance for the club following his move from Ajax this summer.
Mendy is missing the league game with an injury he's picked up during the global break and the new shot-stopper will be frustrated that he won't be able to knuckle down with a run of games.
Hasenhuttl, who worked with Werner in Leipzig before taking on the Southampton job, nevertheless has full faith that his former charge will soon start finding the net. He is really hard to defend against, ' the manager told reporters ahead of the Saints' weekend clash with Chelsea at Stamford Bridge.
"He is a good striker for Chelsea and he is only happy when he scores, so I hope he is unhappy after the game". It's just game minutes that we need for him now. Chelsea should be just too strong, though. They have plenty of other good players in the squad. I know this player very well.
"We don't expect the best game from us at the moment, but they are also struggling with a lot of players going on global travels, so the team that finds quicker in the game and better in the game has a big chance to win it".
Meanwhile, Malian winger Djenepo, who scored his first league goal in over a year in Southampton's 2-0 win over West Bromwich Albion last time out, picked up a hamstring injury in the same match.
It's Chelsea vs Southampton at Stamford Bridge, in the 2020/21 Premier League season.
Both sides are of course in action following a two-week worldwide break in which Saints had eight first-team players in action, and Chelsea eve more, which has taken its toll on the squad.