OAKLAND  (AP) — Bob Melvin knows new contracts are rare in losing seasons, so he is cherishing Oakland’s commitment to him as a long-term leader of the organization.

The Athletics manager received a two-year contract extension Wednesday that takes him through the 2018 season.

“It’s not lost on me that during a year like this, these are things that don’t typically happen,” Melvin said. “I’m very fortunate and appreciative for that. As a team this year I believe we’ve underachieved. The one thing that the front office has always done for me here is given me good players. We’ve underachieved this year, and I’m responsible for that.

“I’m fully committed to this team, this organization and this fan base to get this thing turned around sooner than later,” he said.

General manager Billy Beane made the announcement with the A’s sitting as the worst team in the American League this year following three straight playoff seasons. Oakland headed into Wednesday night’s series finale against the AL West-leading Astros at 60-79 but with wins in the previous two games against first-place Houston.

“By the way, not all the players I gave you were good,” Beane said to Melvin.

Oakland is in rebuilding mode once again and traded away a trio of All-Stars last offseason, losing third baseman Josh Donaldson, catcher Derek Norris and outfielder Brandon Moss.

Beane has been committed to keeping the manager position stable for the future with the small-budget A’s — and Melvin led the club to the playoffs in each of his first three full seasons as skipper. They are 385-339 under his direction.

“I want him around as we go through this transition. He was the right guy for the last generation, and he’ll be the right guy for the next generation,” Beane said of a deal that has been done for some time. “Well-deserved. It’s somebody we feel very proud to have running the club.”

In 2012, Oakland became the first team in major league history to win a division or pennant after trailing by five games with fewer than 10 to play, sweeping three games against Texas to win the division over the Rangers.

Oakland lost to Detroit 3-2 in a best-of-five AL division series that year while returning to the playoffs following a five-year drought without a winning record or playoff berth, finishing 94-68. The A’s lost to Detroit in a five-game first-round series again in 2013, then 9-8 in 12 innings to the AL champion Kansas City Royals in the one-game wild card last fall.

The 53-year-old Melvin, a former big league catcher who grew up in Menlo Park and played at Cal, took over from the fired Bob Geren in June 2011. Melvin led the Diamondbacks to the NL West title in 2007 and also won 93 games in his rookie season with Seattle in 2003.

“This is where I want to be, this is where I’ve wanted to be,” Melvin said. “This is the most comfortable place for me, it’s home for me.”

Melvin received a two-year contract extension in January 2013 that was to take him through the 2016 season. He is 878-847 in 12 years as a manager.

“We’ve had some changes in the last couple years but when you keep the leader in his place, that’s what you need. You need consistency from the top,” catcher Stephen Vogt said. “Having Bob around with this group and our young core, this team’s going to be good for a long time, especially if he’s the leader. You take him out of this equation, you never know what could happen. It’s good to see that he’s sticking around. We love playing for him.”