He played 52 games last year and 64 games the year before. So he played full seasons both years. He's been an everyday player since Colorado claimed him off waivers from Dallas in 2017 as a 24 year old - spending significant time as a top 4 guy on Colorado and then Detroit.
Patrik Nemeth Stats | Hockey-Reference.com
You read his stat line wrong, he got traded to Colorado at the dealine and the 13 gp listed there is his 13 games played with Colorado post deadline - he played 39 games will Detroit pre-trade.
Miller has looked mostly very good after his shaky preseason. Not sure in what dimension him being sent down would be a possibility when he's arguably been our best LD so far with Lindgren looking a bit out of sorts.
Personally I think people are being too hard on Nils. He hasn't wowed at all and he has some shortcomings so far, but the only way for him to get acclimated is to keep playing him.
I feel like he's looked better the past few games, minimizing mistakes and playing simple. He def needs to improve all around and especially in his puck moving and breakouts but that will come with time. Gallant is doing the right thing by riding him and giving him a chance to acclimate himself.