The 2010 Seattle Mariners season was the 34th season in franchise history. The Mariners finished the season with 61 wins and 101 losses. As the Texas Rangers won their first pennant that season, the Mariners became one of only two teams to have never played in the World Series, along with the Washington Nationals. The Nationals, however, eventually made it to, and won, the World Series 9 years later, leaving the Mariners as the sole franchise to have not played in the Fall Classic.

Offseason

Coaching staff changes Most of the 2009 major league coaching staff was retained, with the exception of third base coach Bruce Hines. Mike Brumley was named the new third base coach on October 30, 2009. On December 7, the Mariners announced their minor league staff. Eriberto Menchaca, who managed the Class-A Clinton LumberKings in 2009, was moved to the rookie-level Pulaski Mariners, Jesus Azuaje was named manager of the rookie-level Peoria Mariners, Tim Laker was named the manager of the Double-A West Tenn Diamond Jaxx, and Andy Fox was named hitting coach for the Diamond Jaxx.

Roster changes

Key departures

On October 19, 2009, catcher Kenji Johjima, the first Japanese-born catcher in Major League Baseball, exercised an opt-out clause in his contract and returned to playing in Nippon Professional Baseball. The Mariners also lost their home run leader, Russell Branyan, who declined a one-year deal with the Mariners to test the free agent market. Two-time Gold Glove winner Adrián Beltré opted for free agency on November 5, 2009, and later signed with the Boston Red Sox. The third baseman declined $12 million in arbitration from the Mariners only days after the team signed Chone Figgins (see below). Beltre officially parted ways with the Mariners when he signed a one-year, $9 million deal with the Boston Red Sox. Pitcher Phillippe Aumont, noted as one of the top prospects in the organization, was sent to the Phillies in the trade for Cliff Lee. Also, pitcher Brandon Morrow was traded to the Toronto Blue Jays as well. Carlos Silva, whose time in Seattle was plagued by injury, was traded to the Chicago Cubs on December 18.

Major league acquisitions Chone Figgins signed a four-year contract valued at $36 million. General manager Jack Zduriencik noted Figgins' versatility on defense and could ask him to play second base as well.

Ken Griffey Jr. returned to the Mariners with a one-year deal after a successful 2009 season and large number of Seattle fans asking for "one more year." Shortstop Jack Wilson signed a two-year, $10 million deal to remain in Seattle. Wilson was one of the players received from the Pittsburgh Pirates at the trading deadline in 2009.

On December 14, 2009, the Mariners, along with the three other organizations including the Philadelphia Phillies, the Toronto Blue Jays, and the Oakland Athletics agreed to a 4-team, 9-player deal. The Mariners received former Cy Young Award winner Cliff Lee from Philadelphia in exchange for three prospects as a complement to ace Félix Hernández.

On December 18, 2009, the Mariners traded pitcher Carlos Silva and cash considerations to the Chicago Cubs for outfielder Milton Bradley, particularly noting his offensive capabilities. On December 22, the Mariners traded Brandon Morrow to the Toronto Blue Jays for pitcher Brandon League, and a minor league prospect. The Mariners acquired first baseman Casey Kotchman from the Boston Red Sox in exchange for utility player Bill Hall, a player to be named later, and cash considerations. On January 29, 2010, the Mariner signed outfielder Eric Byrnes to a one-year, $400,000 contract after he was released by the Arizona Diamondbacks. The Mariners signed first baseman Ryan Garko to a one-year $550,000 contract on February 1. On February 6, the Mariners re-signed pitcher Érik Bédard to a one-year, $1.5 million contract, with a mutual option for 2011.

Minor league acquisitions

After the World Series, the Mariners cleared five spots from their 40-man roster after infielder Bryan LaHair, pitchers César Jiménez, Randy Messenger and Marwin Vega were outrighted to the Triple-A Tacoma Rainiers, and pitcher Justin Thomas was claimed off waivers by the Pittsburgh Pirates. The Mariners added seven new scouts after the season including the West Coast Supervisor Butch Baccala, Southern California scout John Ramey, Northwest scout Joe Ross, Midwest scout Tony Russo, Southwest scout Jess Kapellusch, Atlantic scout Mike Moriarty, and Gulf Coast scout Devitt Moore.

On November 25, the Mariners re-signed minor league pitchers Steve Bray and Steven Shell, and catcher José Yépez. On December 9, the Mariners signed outfielder Corey Patterson to a minor league contract with an invitation to spring training. It was reported by Baseball America that the Mariners signed pitcher Levale Speigner and infielder Travis Denker, and also re-signed pitcher Chris Seddon and Josh Wilson to minor league contracts on December 12. On December 16, the Mariners signed 19-year-old Brazilian prospect Pedro Okuda to a minor league contract. During the trade for Cliff Lee, the Mariners gave up three prospects including pitchers Phillippe Aumont and J. C. Ramírez and outfielder Tyson Gillies.

On December 22, Baseball America reported that the Mariners re-signed pitcher Mike Koplove, and signed pitcher David Pauley, and catcher Ralph Henriquez Jr. During the trade for Brandon League, the Mariners also acquired minor league outfielder Johermyn Chávez from the Blue Jays. On December 28, the Mariners signed catcher Josh Bard, and re-signed pitcher Chad Cordero to minor league contracts with invitations to spring training. The Mariners signed free agent utility player Chris Woodward, who was in their organization during the first half of the 2009 season, to a minor league contract with an invitation to spring training. On January 13, the Mariners re-signed first baseman Brad Nelson to a minor league contract with and invitation to spring training. Formerly of the Milwaukee Brewers organization, Jesús Colomé signed a minor league contract with an invitation to spring training with the Mariners on February 10. On February 12, 2010, the Mariners signed Mike Sweeney, a player who MLB.com called a "key clubhouse component from the Mariners' dramatic 2009 turnaround", to a minor league contract with an invitation to spring training.

+ Baseball America's Top 10 Prospects: Seattle MarinersRankPlayerPosition 1 Dustin Ackley Second baseman 2 Michael Saunders Outfielder 3 Adam Moore Catcher 4 Alex Liddi Third baseman 5 Carlos Triunfel Infielder 6 Michael Pineda Right-handed pitcher 7 Nick Franklin Shortstop 8 Greg Halman Outfielder 9 Dan Cortes Right-handed pitcher 10 Mario Martínez Corner infielder

Minor league rankings During the offseason, MLB.com ranked Mariners' first round draft Dustin Ackley as the 15th best prospect in Minor League Baseball. Ackley was also named the best prospect in the Mariners' organization by Baseball America, followed by outfielder Michael Saunders, catcher Adam Moore, third baseman Alex Liddi, infielder Carlos Triunfel, pitcher Michael Pineda, shortstop Nick Franklin, outfielder Greg Halman, pitcher Dan Cortes, and corner infielder Mario Martínez. Baseball America also ranked players by their specific talents. Ackley was named best hitter for average, Halman was named best hitter for power, and best athlete, outfielder Ezequiel Carrera was named both best strike-zone discipline, and fastest base runner, Pineda was named as having the best fastball, and the best control of pitches, pitcher Josh Fields was named as having the best curveball, pitcher Steven Hensley was named as having the best slider, pitcher Nick Hill was named as having the best changeup, Steve Baron was named the best defensive catcher, Gabriel Noriega was named the best defensive infielder, Triunfel was named as having the best throwing arm amongst infielders, Saunders was named best defensive outfielder, and James Jones was named as the having the best throwing arm amongst outfielders.

Salary arbitration Five Mariners' players filed for salary arbitration in January 2010. The list of filers included pitchers David Aardsma, Félix Hernández, Brandon League and Mark Lowe, and first baseman Casey Kotchman. On January 18, Aardsma, Hernández and Lowe signed new contracts with the Mariners, avoiding arbitration. Aardsma signed a deal for $2.75 million, and Lowe signed a deal worth $1.15 million. Hernández's five-year deal was worth $80 million. On January 20, the Mariners came to an agreement with League for a one-year $900,000 deal, avoiding arbitration. Kotchman, the last arbitration eligible player on the Mariners roster, agreed to a $3.5 million contract on February 3, avoiding arbitration, and settling all the Mariners' arbitration cases.

Complete transactions Source for official major league transactions

2009

October October 19: Justin Thomas designated for assignment. Ten days later, he was claimed by the Pittsburgh Pirates off waivers. October 29: Outrighted pitchers César Jiménez, Randy Messenger and Marwin Vega, and first baseman Bryan LaHair to the Triple-A Tacoma Rainiers.

November November 4: Claimed Yusmeiro Petit off waivers from the Arizona Diamondbacks. November 20: Pitcher Chris Jakubauskas claimed off waivers by the Pittsburgh Pirates. Pitcher Robert Manuel claimed off waivers by the Boston Red Sox. Called-up pitchers Dan Cortes, Ricky Orta, Edward Paredes, J. C. Ramírez and Anthony Varvaro. Outrighted infielder Josh Wilson to Triple-A Tacoma. Activated pitchers Ryan Feierabend and Sean White from the disabled list. Signed catcher Eliézer Alfonzo to a minor league contract.

December December 8: Signed third baseman Chone Figgins to a four-year, $36 million contract. December 10: Signed center fielder Corey Patterson to a minor league contract. Selected pitcher Kanekoa Texeira from the New York Yankees in the Rule 5 draft. Re-signed shortstop Jack Wilson to a two-year, $10 million contract. December 16: Signed shortstop Pedro Okuda to a minor league contract. Traded pitchers J. C. Ramírez and Phillippe Aumont and outfielder Tyson Gillies to the Philadelphia Phillies for pitcher Cliff Lee. December 18: Re-signed outfielder Ryan Langerhans to a minor league contract. Traded pitcher Carlos Silva to the Chicago Cubs for outfielder Milton Bradley. December 23: Traded pitcher Brandon Morrow to the Toronto Blue Jays for pitcher Brandon League and outfielder Johermyn Chávez. December 28: Signed catcher Josh Bard and pitcher Chad Cordero to minor league contracts.

2010

January January 6: Signed outfielder Chris Woodward to a minor league contract. January 7: Traded utility player Bill Hall to the Boston Red Sox for first baseman Casey Kotchman. January 13: Re-signed first baseman Brad Nelson to a minor league contract. January 15: Claimed first baseman Tommy Everidge off of waivers from the Oakland Athletics. January 29: Signed outfielder Eric Byrnes to a one-year $400,000 contract. First baseman Tommy Everidge designated for assignment.

February February 1: Signed first baseman Ryan Garko to a one-year, $550,000 contract. Pitcher Pitcher Gaby Hernandez designated for assignment. February 3: Outrighted first baseman Tommy Everidge to the Triple-A Tacoma Rainiers. February 6: Re-signed pitcher Érik Bédard to a one-year, $1.5 million contract. Pitcher Pitcher Yusmeiro Petit designated for assignment. February 10: Signed pitcher Jesús Colomé to a minor league contract with an invitation to spring training. Pitcher Yusmeiro Petit outrighted to the Triple-A Tacoma Rainiers. Pitcher Gaby Hernandez claimed off waivers by the Boston Red Sox. February 12: Signed designated hitter Mike Sweeney to a minor league contract with an invitation to spring training.

March March 3: Pitchers Kenn Kasparek and Anthony Vasquez assigned to the Mariners.