The 24-year-old joined Sam Allardyce's men on a four-and-a-half-year deal from Leicester City in January.
Having struggled to break into the starting team, Schlupp was handed a rare start - in defence - in a 1-0 win over Watford - before the international break.
“We’re not making as many mistakes as we were and we’re creating a lot more,” Hennessey said, as reported by London News Online.
“The back four have been fantastic, they’ve been so solid and good as a unit.
“We were unlucky with Patrick [van Aanholt], it was a nasty injury at West Brom but Jeffrey has come in and he’s done really well and didn’t even look like he hadn’t played many games.
"He’s really happy with himself.”
Schlupp was a member of Leicester's historic side that lifted the league title last season, making 24 appearances.
This season, however, he struggled for first team opportunities, and after only four appearances in the first half of the campaign, he thought the time was right to move on.