TALLADEGA, Ala. (AP) – Mark Martin will leave Roush Racing at the end of this season to drive a partial NASCAR Nextel Cup schedule for MB2 Racing, The Associated Press learned Thursday night.

Team owner Jack Roush, who has fielded a Ford for Martin in NASCAR’s top stock car series since 1988, will make the announcement this morning at Talladega Superspeedway, according to a source who asked that he not be identified because all details of the deal have not been finalized.

MB2 general manager Jay Frye has scheduled a press conference for later this morning at the Talladega track, where the Cup cars will race Sunday.

Martin will share the ride in the No. 01 Chevrolet with rookie Regan Smith, a 23-year-old regular in the Busch Series, according to the source. Joe Nemechek, currently racing in the No. 01, will remain with MB2, but will move to a third team entry, while Sterling Marlin will stay in the team’s No. 14 Chevy.

The 47-year-old Martin has been talking about retirement from the Cup series for the past two seasons. He was set to give up his ride in the No. 6 Roush Ford after the 2005 season, but was convinced by Roush to stay another year because none of the team’s young drivers were ready to step into the ride.

Earlier this season, it appeared Martin would leave Cup in 2007 to drive a full schedule for Roush in the Craftsman Truck Series, but he recently began talking about the possibility of running at least a partial schedule in Cup.

Roush team president Geoff Smith said several weeks ago that the team would definitely not field a Cup car for Martin in 2007 and that they were close to completing a deal with Martin to drive a Roush truck. But that deal apparently fell apart after the MB2 ride became available.

Martin, who drove his first Cup race in 1981, has started 667 Cup races and has 35 victories, 234 top five finishes and 372 top 10s. The versatile Martin also owns a Busch Series-record 47 wins and has five more in trucks. He also has 13 victories and a record five championships in the all-star IROC series.