ATLANTA — John Smoltz has reached preliminary agreement on a contract with the Boston Red Sox, who also agreed today to a one-year contract with outfielder Rocco Baldelli.

A person familiar with the negotiations, speaking on condition of anonymity because the final paperwork had not been completed, said Smoltz will sign a guaranteed deal with the Red Sox worth about $5 million and also have the possibility of earning another $5 million in performance bonuses. The deal was expected to be finalized later today.

Smoltz, the only pitcher in baseball history with 200 wins and 150 saves, had pitched for the Braves since 1988. The 41-year-old is coming off major shoulder surgery that sidelined him for most of last season, but feels healthy enough to pitch at least one more year.

The deal, which also was reported by several other media outlets, means that Smoltz will likely finish his career with a team other than the Braves — a startling development given his long history with the team. He was an unknown minor leaguer when acquired from Detroit in 1987 for Doyle Alexander, but went on to become a cornerstone of Braves' teams that won a record 14 straight division titles from 1991-2005.

Smoltz apparently turned to the Red Sox after the Braves balked at giving him more than a $3 million deal, the person said. Atlanta general manager Frank Wren declined comment when reached by e-mail, and there was no immediate comment from Boston officials.

Smoltz began his career as a starter, winning 24 games and the NL Cy Young Award in 1996. Numerous elbow problems led him to shift to the bullpen to relieve the stress on his arm, and he set an NL record with 55 saves in his first full season as a closer in 2002.

After three years finishing games for the Braves, Smoltz moved back to the rotation in 2005 and didn't miss a beat, going 14-7 with a 3.06 ERA. He went 47-26 in his second run as a starter, but shoulder pain cut short the 2008 season after only six appearances.

Smoltz tried to pitch one game as a reliever, then underwent surgery to fix what he said were "five or six problems," including his labrum, AC joint and biceps.

While acknowledging that similar operations have end the careers of many others, Smoltz felt encouraged enough about his rehabilitation to begin making plans for the new season. The Braves, however, were reluctant to make a deal with the aging pitcher, especially coming off a dismal season in which they missed the playoffs for the third year in a row.

Still, the loss of Smoltz figures to create a major public-relations for a franchise that has fallen on hard times since the longest stretch of postseason appearances in baseball history.

Atlanta's only major acquisition of the offseason has been pitcher Javier Vazquez, obtained in a trade with the Chicago White Sox. Wren failed to work out a deal for San Diego ace Jake Peavy and another top pitcher, free agent A.J. Burnett, rebuffed an offer from the Braves to sign with the New York Yankees.

In Thursday's other move, the Red Sox added Baldelli, who spent the majority of last season on the disabled list for the AL champion Tampa Bay Rays. The 27-year-old batted .263 with four home runs and 13 RBI in 28 games.