West Ham keeper Henderson welcomes Jaaskelainen competition
The pair are competing for No1 status this season after Robert Green's move to QPR.
Anderson told WHUTV: "I feel like I've developed and I feel myself getting fitter and fitter. I'm working well with the goalkeeper coach Marge [Martyn Margetson] and I'm hoping to get a chance to show the fans what I'm about.
"Me and Jussi are room-mates and very close. He's a great goalkeeper who's played over 500 games in the Premier League so it's great to have him around."