Letang was hurt late in Friday night's loss to Carolina and was scratched from Saturday's game against the Hurricanes.
Coach Mike Johnston described Letang as day to day and didn't rule out having the defenseman return to the lineup this week. Letang has four goals and 14 assists in 22 games for the Metropolitan Division-leading Penguins.
Forward Marcel Goc could play against New Jersey. He did not play on Saturday night with what Johnston described as a bruise.
Forward Beau Bennett remains out indefinitely with a lower-body injury. Defenseman Paul Martin received several stitches after getting hit with a puck during practice on Monday but is not expected to miss any time.