VANCOUVER, British Columbia -- The Pittsburgh Penguins will begin a crucial four-game western road trip without forward Bryan Rust.

Rust, 31, stayed behind in Pittsburgh while dealing with an upper-body injury suffered in the third period of a 7-6 win over Philadelphia on Sunday.

Rust's 18 goals are third on the team behind captain Sidney Crosby and Jake Guentzel. The 10-year veteran has been coming on strong of late, with seven goals in his last eight games, including two against the Flyers.

The Penguins are already without Guentzel, who is on injured reserve with an upper-body injury. Guentzel did travel with the team to start the four-game trip that begins Tuesday night in Vancouver, but he's ineligible to come off injured reserve until March 10.

Reilly Smith replaced Rust on the top line alongside Crosby and Rickard Rakell during practice on Monday.

The Penguins entered Monday seven points out of a playoff spot in the Eastern Conference, though they have multiple games in hand over most of the teams they are chasing for a postseason berth.