WCXX

(CNN) -- Though still in critical-but-stable condition, Tracy Morgan is continuing to show signs of improvement, his publicist said Thursday.

"Today was a better day," Lewis Kay said, adding that Morgan's medical team remains optimistic that his recovery is progressing.

The actor-comedian was seriously injured early Saturday after a Walmart truck slammed into the limo car occupied by Morgan and four others on the New Jersey Turnpike. The collision killed comedian James McNair and injured the others. Morgan was hospitalized with broken ribs, a broken nose, a broken femur, and a broken leg.

Passengers Ardie Fuqua, Jeffrey Millea and Harris Stanton also were injured in the crash; Stanton is the only person since released from the hospital.

The truck driver, Kevin Roper, turned himself in to police the night of the crash. Roper pleaded not guilty Wednesday to charges that include vehicular homicide and assault by auto. In a criminal complaint, police said Roper has been awake for more than 24 hours at the time of the crash.

Morgan is likely to remain in the hospital for the next several weeks, Kay said.

Morgan was a regular on "Saturday Night Live" for seven years and later received an Emmy nomination for his role in the comedy series "30 Rock."

He was scheduled to start shooting a 10-episode FXX comedy series in August. Parent company FX Network said Morgan's show would be waiting for him after his recovery.

CNN's Alexa Miranda, Faith Karimi, and Ray Sanchez contributed to this report.