Rangers are moving to bring striker Joe Garner to Ibrox.
Newcastle take on Reading this Wednesday, having lost their opening two Championship games.
The Owls have reportedly bid for David Jones.
Henderson suggested the side needs to work on managing games when they are in the lead as one of the areas to work on.
Former Crystal Palace defender Adrian Mariappa was released by the Eagles this summer.
Spurs narrowly missed out on the Premier League title before England failed to capture the imagination at the European Championships.
The Blues goalkeeper was in impressive form in their opening day draw with Tottenham.
Newcastle United have been quite busy in the summer transfer window so far.
The West Ham United defender backs Manchester City to win the Premier League title this season.
Coutinho got off the mark with a brace against Arsenal.