The Dane is not expected to play again this season, and his contract expires in June.
Despite saying this week: "I love Newcastle and I want to stay here", the 32-year-old has already told his agent to find him a new club next term.
Løvenkrands will end his time at Newcastle stuck on 99 career goals.
His last was an extra-time penalty as Newcastle were knocked out of the League Cup by Blackburn Rovers in October
Alan Pardew: “It’s not comfortable for him or us, if I’m honest.
“We all know he’s a proper lad, so we are disappointed.”
“It’s a bad injury.
“We have probably lost him for the season. In training he had a shot and we think he’s really badly hurt his thigh. It’s a definite tear and maybe a rupture.”
The last time Newcastle released Løvenkrands he quickly returned.
He was let go after a disappointing six-month stint ended with relegation to the Championship in 2009.
But Newcastle took him back in September, and he scored 16 goals as they won promotion.
Signed as a free agent on both occasions, the former Rangers, Schalke and Copenhagen player made 85 Magpies appearances, scoring 29 goals.