Offseason

• December 8, 1977: Al Oliver
  Al Oliver
  Albert Oliver, Jr. is a former Major League Baseball player. Over the course of his 18-year career, he played for the Pittsburgh Pirates , Texas Rangers , Montreal Expos , San Francisco Giants , Philadelphia Phillies , Los Angeles Dodgers and Toronto Blue Jays...
  
   and Nelson Norman
  Nelson Norman
  Nelson Augusto Norman is a former Major League Baseball shortstop, minor league coach and manager. He played all or part of six seasons in the major leagues between and .- Pittsburgh Pirates :...
  
   were traded by the Pirates to the Texas Rangers
  Texas Rangers (baseball)
  The Texas Rangers are a professional baseball team in the Dallas-Fort Worth Metroplex, based in Arlington, Texas. The Rangers are a member of the Western Division of Major League Baseball's American League, and are the reigning A.L. Western Division and A.L. Champions. Since , the Rangers have...
  
   as part of a four-team trade. Bert Blyleven
  Bert Blyleven
  Bert Blyleven is a former Major League Baseball pitcher who played from to , and was best known for his curveball. Blyleven was inducted into the Baseball Hall of Fame in 2011...
  
   was traded by the Rangers to the Pirates, and John Milner
  John Milner
  John David Milner was an American first baseman and left fielder in Major League Baseball. A native of Atlanta, Georgia, he grew up a huge Hank Aaron fan, even appropriating his idol's nickname, "The Hammer." He was a member of the "We Are Family" Pittsburgh Pirates team that won the World Series...
  
   was traded by the New York Mets
  New York Mets
  The New York Mets are a professional baseball team based in the borough of Queens in New York City, New York. They belong to Major League Baseball's National League East Division. One of baseball's first expansion teams, the Mets were founded in 1962 to replace New York's departed National League...
  
   to the Pirates. Willie Montañez
  Willie Montañez
  Guillermo Montañez Naranjo is a former Major League Baseball first baseman. Even though he was productive, Montañez often carried the label "hot dog" for the whimsical manner in which he approached the game. After hitting home runs, he would trot very slowly around the bases, shuffling his feet on...
  
   was traded by the Atlanta Braves
  Atlanta Braves
  The Atlanta Braves are a professional baseball club based in Atlanta, Georgia. The Braves are a member of the Eastern Division of Major League Baseball's National League. The Braves have played in Turner Field since 1997....
  
   to the Mets, and the Rangers traded Tom Grieve
  Tom Grieve
  Thomas Alan Grieve was a Major League Baseball player from 1970-1979 for the Washington Senators, Texas Rangers, New York Mets and St. Louis Cardinals...
  
   and a player to be named later to the Mets. The Rangers traded Adrian Devine
  Adrian Devine
  Paul Adrian Devine was a Major League Baseball pitcher from 1973 to 1980 for the Atlanta Braves and Texas Rangers. Devine primarily pitched in relief and had his best season in 1977 with the Rangers when he posted a win-loss record of 11–6 with 15 saves. He and his wife breed Cavalier King...
  
  , Tommy Boggs
  Tommy Boggs
  Thomas Winton Boggs is a former professional baseball pitcher. Boggs pitched in all or part of nine seasons in Major League Baseball between 1976 and 1985....
  
  , and Eddie Miller
  Eddie Miller (outfielder)
  Edward Lee Miller , is a retired Major League Baseball player who played outfielder from - for the Texas Rangers, Atlanta Braves, Detroit Tigers, and San Diego Padres. Miller's only major league home run came in his last career at bat.-External links:...
  
   to the Braves. The Mets traded Jon Matlack
  Jon Matlack
  Jonathan Trumpbour Matlack is an American former Major League Baseball left-handed pitcher...
  
   to the Rangers. The Rangers completed the deal by sending Ken Henderson
  Ken Henderson
  Kenneth Joseph Henderson was an outfielder for the San Francisco Giants , Chicago White Sox , Atlanta Braves , Texas Rangers , New York Mets , Cincinnati Reds and Chicago Cubs .He helped the Giants to win the National League Western Division in 1971 and the Reds to win the NL West in...
  
   to the Mets on March 15, 1978.
• March 18, 1978: Carl Morton
  Carl Morton
  Carl Wendle Morton was a former starting pitcher in Major League Baseball who played for the Montreal Expos and Atlanta Braves...
  
   was released by the Pirates.

Notable transactions

• April 4, 1978: Miguel Diloné
  Miguel Dilone
  Miguel Ángel Diloné Reyes is a former Major League Baseball switch hitting outfielder. He played 12 seasons with the Pittsburgh Pirates, Oakland Athletics, Chicago Cubs, Cleveland Indians, Chicago White Sox, Montreal Expos and San Diego Padres.Dilone began his career as a September call-up in 1974...
  
  , Elias Sosa
  Elias Sosa
  Elías Sosa Martínez , is a former right-handed relief pitcher in Major League Baseball. He was signed by the San Francisco Giants as an amateur free agent on March 4, 1968. He played for the Giants , St...
  
   and a player to be named later were traded by the Pirates to the Oakland Athletics
  Oakland Athletics
  The Oakland Athletics are a Major League Baseball team based in Oakland, California. The Athletics are a member of the Western Division of Major League Baseball's American League. From to the present, the Athletics have played in the O.co Coliseum....
  
   for Manny Sanguillén
  Manny Sanguillen
  Manuel De Jesus Sanguillen Magan, better known as Manny Sanguillen or "Sangy" , is a former professional baseball player who was a catcher in the Major Leagues. He was named to the All-Star team three times, in , , and . He played primarily for the Pittsburgh Pirates, but also for the Oakland...
  
  . The Pirates completed the deal by sending Mike Edwards
  Mike Edwards (second baseman)
  Michael Lewis Edwards is a former Major League Baseball second baseman. He played all or part of four seasons in the majors from until...
  
   to the Athletics on April 7.
• June 1, 1978: Jim Fregosi
  Jim Fregosi
  James Louis Fregosi is a former Major League Baseball shortstop and manager. During an 18-year baseball career, he played from 1961–1978 for four different teams, primarily the Los Angeles and California Angels. In that franchise's first eleven years of play, he became its first star as the team's...
  
   was released by the Pirates.
• June 6, 1978: Vance Law
  Vance Law
  Vance Aaron Law is a former third baseman in Major League Baseball. From through , he played for the Pittsburgh Pirates , Chicago White Sox , Montreal Expos , Chicago Cubs , and Oakland Athletics . He also played one season in Japan for the Chunichi Dragons in 1990. Law batted and threw...
  
   was drafted by the Pirates in the 39th round of the 1978 amateur draft
  1978 Major League Baseball Draft
  -First round selections:The following are the first round picks in the 1978 Major League Baseball draft.- Background :In 1978, four players made the jump from amateur baseball to the major leagues, including Arizona State third baseman Bob Horner, who was selected number one overall by the Atlanta...
  
  .
• September 22, 1978: Cito Gaston
  Cito Gaston
  Clarence Edwin "Cito" Gaston is a former Major League Baseball outfielder and manager. His major league career as a player lasted from 1967–1978, most notably for the San Diego Padres and the Atlanta Braves...
  
   was purchased by the Pirates from the Atlanta Braves
  Atlanta Braves
  The Atlanta Braves are a professional baseball club based in Atlanta, Georgia. The Braves are a member of the Eastern Division of Major League Baseball's National League. The Braves have played in Turner Field since 1997....
  
  .

Roster

Starters by position

Other batters

Starting pitchers

Other pitchers

Relief pitchers

Farm system