The Germany striker is now struggling for form after an impressive start to his first season in the Premier League.
"Nick Woltemade? I feel sorry for the lad a bit," Waddle told Ozoon. "I had to move out to France and it doesn't just happen overnight. He should be settled in now though. It took me three months to get myself together, for him the jury's still out with the fans.
"A lot of Geordie fans I speak to are not keen on him or Yoane Wissa, by the way. They think they were both panic buys. I don't know if Wissa was ever intended to be the number nine.
"I think if Alexander Isak was here he would have probably played on the right side. They're playing Anthony Gordon down the middle at the minute. The problem is if he starts thinking he's a centre forward he becomes a bad player.
"When you're a winger, I played up front when I went from the wing, and you'd automatically run down the channels a bit because you want to get the ball in an area which you're used to, which are the flanks, and you cause a lot of problems. But when you start thinking you're a centre forward it becomes a problem because you stop making those runs.
"Anthony Gordon's banging them in when he plays down the middle and I can see Eddie Howe thinking, 'I've got two centre forwards which would cost us an absolute fortune sat on the bench, basically.' they've not hit the ground running.
"I know Wissa had an injury, but looking at the body language and looking at how they play, they just don't look like Newcastle type of players. A few goals can turn your confidence and turn everything around, I know that. But at the minute, for those two guys, I find it very, very hard.
"I think the fans are thinking, this is not the answer for replacing Isak. There's talk of Woltemade going back to Germany. I think if they got the price right, I think it could be a deal on there."