Ryan Newman will lose his NASCAR Sprint Cup seat with Stewart-Haas when Kevin Harvick joins from Richard Childress Racing next season.
Harvick's deal with Tony Stewart's squad had been completed last season.
It was previously unclear whether SHR would expand to a fourth car to accommodate Harvick alongside existing drivers Stewart, Newman and Danica Patrick, but at New Hampshire Motor Speedway on Friday Stewart announced that Newman would be departing.
"We are not ready to expand to a fourth team," Stewart said. "Unfortunately, this will be the last year that we have Ryan with us.
"That's probably what has made this a bittersweet day. I'm bringing in another one of my friends to the organisation, but also knowing that I'm losing a friend from the organisation at the end of the year.
"I truly wish we were able to facilitate four teams at this time. We're just not able to do that."
Newman joined Stewart-Haas from Penske in 2009 when Stewart linked up with Gene Haas to create the operation.