Offseason

• December 8, 1976: Greg Gross
  Greg Gross
  Gregory Eugene Gross , is a former professional baseball player who played in the Major Leagues from 1973-1989, playing for the Chicago Cubs, Houston Astros, and Philadelphia Phillies...
  
   was traded by the Astros to the Chicago Cubs
  Chicago Cubs
  The Chicago Cubs are a professional baseball team located in Chicago, Illinois. They are members of the Central Division of Major League Baseball's National League. They are one of two Major League clubs based in Chicago . The Cubs are also one of the two remaining charter members of the National...
  
   for Julio González
  Julio González (infielder)
  Julio César González Hernández is a former Major League Baseball infielder. He played all or part of seven seasons in the majors from until . He played about equally at shortstop and second base, with a lesser but still substantial number at third base.-Sources:...
  
  .
• January 11, 1977: John Butcher
  John Butcher (baseball)
  John Daniel Butcher is a former Major League Baseball pitcher who played for seven seasons. He played for the Texas Rangers from 1980 to 1983, the Minnesota Twins from 1984 to 1986, and the Cleveland Indians in 1986....
  
   was drafted by the Astros in the 1st round (5th pick) of the secondary phase of the 1977 Major League Baseball Draft
  1977 Major League Baseball Draft
  -First round selections:The following are the first round picks in the 1977 Major League Baseball draft.- Background :The White Sox raised some brows when they passed on right-handed pitcher Bill Gullickson, a native of nearby Orland Park, IL, and selected outfielder Harold Baines as the number one...
  
  , but did not sign.
• January 25, 1977: Paul Siebert
  Paul Siebert
  Paul Edward Siebert is a former Major League Baseball pitcher. He pitched parts of five seasons in the majors, from until . Paul's father was former major league first baseman Dick Siebert....
  
   was traded by the Astros to the San Diego Padres
  San Diego Padres
  The San Diego Padres are a Major League Baseball team based in San Diego, California. They play in the National League Western Division. Founded in 1969, the Padres have won the National League Pennant twice, in 1984 and 1998, losing in the World Series both times...
  
   for Mike Allen (minors).
• March 26, 1977: Rob Andrews
  Rob Andrews (baseball)
  Robert Patrick Andrews is a former professional baseball player. He played five seasons in Major League Baseball, from 1975 until 1979, for the Houston Astros and San Francisco Giants, primarily as a second baseman.-Sources:...
  
   and cash were traded by the Astros to the San Francisco Giants
  San Francisco Giants
  The San Francisco Giants are a Major League Baseball team based in San Francisco, California, playing in the National League West Division....
  
   for Willie Crawford
  Willie Crawford
  Willie Murphy Crawford was a Major League Baseball outfielder who played with Los Angeles Dodgers , St. Louis Cardinals , Houston Astros and Oakland Athletics . Crawford was born in Los Angeles, California. He batted and threw left-handed...
  
   and Rob Sperring
  Rob Sperring
  Robert Walter Sperring was a baseball player who played for the Chicago Cubs from 1974 to 1976 and the Houston Astros in 1977....
  
  .

Notable transactions

• June 7, 1977: Scott Loucks
  Scott Loucks
  Scott Gregory Loucks is a former Major League Baseball outfielder. He played parts of five seasons in the majors between and . In none of those seasons did he accumulate more than 49 at bats or 11 hits. Both of those high-water marks came in for the Houston Astros, when he was used in 44 games,...
  
   was drafted by the Astros in the 5th round of the 1977 Major League Baseball Draft
  1977 Major League Baseball Draft
  -First round selections:The following are the first round picks in the 1977 Major League Baseball draft.- Background :The White Sox raised some brows when they passed on right-handed pitcher Bill Gullickson, a native of nearby Orland Park, IL, and selected outfielder Harold Baines as the number one...
  
  .
• June 15, 1977: Willie Crawford
  Willie Crawford
  Willie Murphy Crawford was a Major League Baseball outfielder who played with Los Angeles Dodgers , St. Louis Cardinals , Houston Astros and Oakland Athletics . Crawford was born in Los Angeles, California. He batted and threw left-handed...
  
   was traded by the Astros 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 Denny Walling
  Denny Walling
  Dennis Martin Walling is a former Major League Baseball player. Walling played all or part of eighteen seasons in the majors, from 1975 to 1992. He played his most games as a third baseman, but also saw significant time as an outfielder and first baseman.Walling may be best known as a...
  
  .

Roster

Starters by position

Other batters

Starting pitchers

Other pitchers

Relief pitchers

Farm system