"I know because I played with him at Bolton last season in the same team and he did very well.
"He did take a little bit of time to settle into the team but he is still a young player.
"And once he was in the team he stayed there and became a regular.
"He did well once he was in despite Bolton struggling."
Speed knows Bolton wanted to keep Guthrie and admits fans at the Reebok will be disappointed to see him join a rival Premier League side.
He added: "The Bolton fans took to Danny straight away and they wanted the club to sign him from Liverpool.
"I think the Newcastle fans will like him too.
"He's energetic and an honest lad. He should do really well."