Phelan M. Ebenhack, File, Associated Press
FILE - In this Dec. 10, 2013, file photo, Arizona Diamondbacks general manager Kevin Towers address reporters at baseball's winter meetings in Lake Buena Vista, Fla. The Diamondbacks have fired Towers on Friday, Sept. 4, 2014.

PHOENIX — The Arizona Diamondbacks have fired general manager Kevin Towers in the midst of a third straight disappointing season.

Towers became Arizona's general manager in 2010 and put together a roster that won 94 games and the NL West in 2011.

The Diamondbacks have backpedaled since then, finishing .500 the past two seasons and struggling this year despite having the highest payroll in franchise history.

Plagued by injuries, Arizona lost 22 of its first 30 games and was 59-81 through Thursday's games.

Towers' firing comes four months after the Diamondbacks hired Hall of Fame manager Tony La Russa as chief operating officer.

The Diamondbacks have offered Towers another position within the front office, but he isn't expected to make a decision until after a new general manager has been hired.

"Over the past three months, I have had the opportunity to evaluate all aspects of our baseball operations and have decided to restructure our staff in order to improve our decision-making process," La Russa said in a statement. "I have the utmost respect for Kevin and a friendship with him that dates back many years which has allowed me to appreciate his talents and experience."

Towers was hired after a successful stint in San Diego, where he served 14 years as the Padres' general manager.

With manager Kirk Gibson at the helm, Arizona won the NL West in 2011, its first division title since 2007.

The Diamondbacks have struggled since then despite a slew of moves by Towers, finishing 81-81 the past two seasons.

Towers and Gibson were given contract extensions during spring training, but the Diamondbacks floundered once the season started, in part because of injuries to key players.

No. 1 starter Patrick Corbin underwent Tommy John surgery before the season started and outfielder Mark Trumbo, the team's top offensive acquisition during the offseason, went down with a stress fracture in his foot after leading the NL in homers the first three weeks of the season. Outfielder A.J. Pollock also missed extended time with a broken hand and All-Star first baseman Paul Goldschmidt was lost for the season with a broken hand last month.

Even before the injuries struck, the Diamondbacks labored after a series of deals by Towers didn't pan out.

The big trade under Towers came before the 2013 season, when the Diamondbacks sent outfielder Justin Upton to the Braves for top pitching prospect Randall Delgado and three minor leaguers. Upton has continued to produce in Atlanta while the players Arizona got in return have yet to have much of an impact.

Towers also have traded away several starting pitches, including Ian Kennedy, Trevor Bauer, Jarrod Parker and Tyler Skaggs, along with outfielder Adam Eaton.

"We are extremely grateful for all that he has done for the D-backs during his four-plus years here, particularly given that he has always put the organization ahead of his own self-interests," La Russa said. "That tells you all you need to know about him as a person."