The Pittsburgh Penguins and GM Jim Rutherford are shopping for bottom lines help. The team has been sheltering its current fourth line with players who have more experience in the AHL than the NHL. However, prices around the league have skyrocketed over the past few weeks as more teams consider signing their free agents or enter the playoff chase. The Penguins trade needs haven’t changed, but the market has.

Friday night, the National Hockey Now family learned the Penguins are on the shortlist of San Jose Sharks center Joe Thornton, according to sources close to the player.

Stick tap to our colleagues at Boston Hockey Now, specifically Jimmy Murphy (@murphyslaw74) for getting the scoop. Murphy was the first to report the Boston Bruins interest in Ondrej Kase, whom Boston acquired today.

This is likely Thornton’s last season and San Jose is giving their stalwart a chance to win a Stanley Cup. The Penguins denied San Jose and Thornton that chance in the 2016 Stanley Cup Final.

On Thornton’s shortlist are Colorado, Boston, Tampa Bay, Dallas, and Pittsburgh.

The source indicated the Penguins have at least kicked the tires with San Jose GM Doug Wilson, in addition to the other teams listed. The situation is said to be “very fluid.”

Thornton has traditionally been strong on the faceoff dot with a 54.3% career percentage. However, he has slumped to 49% this season. A Penguins source did confirm the Penguins are concerned about Nick Bjugstad’s recovery timetable, as it relates to being ready for the stretch run. The Penguins are currently 27th in the league on faceoffs.

Thornton, 40, has 25 points in 60 games this season, including just two goals. The playmaking center has mostly remained the top center in San Jose, playing with Timo Meier and Kevin Lebanc. The centerman is averaging just over 15 minutes of ice time per game.

Jumbo Joe is a six-time all-star and the 2006 winner of the Art Ross Trophy and the Hart Trophy. He also has a connection to the Penguins beyond losing the 2016 Stanley Cup Final. Penguins head coach Mike Sullivan was Thornton’s coach in Boston in 2003-04 and 2005-06 (the 2004-05 season canceled due to a lockout).

Sullivan was the Boston coach when Thornton was traded from Boston to San Jose on Nov. 30, 2005.