Whether you believe Liljegren's already reached his ceiling or you think he still has room to grow into a 20+ minute per night RHD you have to admit it would be typical of the Leafs to sell when his stock is at its absolute lowest.
Of course he would probably be do a small raise on his next contract and the question then becomes, is he worth his next deal for what he brings to the team? Hard to say, he's only ever played for Keefe who jerked him in and out of the lineup like a yo-yo, and let's be honest who was a rookie coach learning on the fly.
Let's trade a 25 year old Dman to make room for a 34 year old Tanev, then let's look back in 3 years and tell me if you would have that move back.