MESA, Ariz. -- In the ever-changing world of the Oakland A's, Billy Butler is one of the clubhouse veterans.
After all, he signed as a free agent back on Nov. 19.
As manager Bob Melvin put it before the A's took the field on Wednesday for their first full-squad workout of the spring, "We have a certain amount of turnover from time to time."
The A's 40-man roster includes 17 players added since the end of last season, starting with Butler. They also signed -- and gave Spring Training invites to -- 12 Minor League free agents, including veteran Barry Zito, a one-time first-round Draft choice of the A's, who was out of the game last season.
"That's the way baseball is," said Melvin. "There are changes everywhere."
There are, however, more changes with Oakland. Not that anyone is complaining. For all the roster juggling they do, the A's have had success, even if a World Series championship has eluded the franchise since 1989.
The A's have advanced to the postseason in each of the three full seasons Melvin has been their manager, winning the American League West in 2012 and 2013 and claiming a Wild Card spot last season.
"It shows you the type of evaluation and scouting the A's do, how good [general manager] Billy Beane and his scouting department is," said Butler, a member of the Royals team that ended a 29-year postseason drought by winning the AL pennant last season. "They don't have a lot of money, but you have to give them credit, because they find talent."
The search is constant.
Melvin was named interim manager of the A's on June 9, 2011. Center fielder Coco Crisp is the only player who was on the roster that day who is still in the organization. Crisp is one of 109 players who has worn the A's uniform and the franchise leader in games played (460) during Melvin's 585-game tenure.
Not that turnover has been a hindrance to Oakland's success on the field. The A's are 325-260 since Melvin became their manager, a .556 winning percentage that is the best in the AL West and ranks behind only the Tigers (.567) and Yankees (.557) in the AL.
During Melvin's three full seasons, the A's are 278-208, a .572 winning percentage, the best regular-season record in the AL.
Not bad for a team that has only three players on its roster who have appeared in 300 games during the Melvin Era -- Crisp, Josh Reddick (379) and infielder Eric Sogard (311).
Melvin has filled out lineup cards with nine players starting at catcher, 15 at first base, 11 at second base, nine at third base, eight at shortstop, 19 in left field, nine in center field and 15 in right field.
"It is kind of mind-blowing, but it's been a fun organization to be part of," said Sogard. "You have to give credit to the front offices. They don't only look at numbers, but they look at character and how guys are in the clubhouse. They find guys who can jell and fit into what we are."
Credit also have to be given to Melvin, who doesn't worry about the constant turnover, and looks for ways to make newcomers feel welcome in a hurry.
Wednesday's team meeting included the introduction of owner Lewis Wolff, whose entrance into the clubhouse was accompanied by the sounds of "Louie, Louie." The meeting concluded with catcher Stephen Vogt doing his best impersonation of Chris Farley as the motivational speaker Matt Foley and explaining the rule changes that Major League Baseball has adopted for the 2015 season.
"We spend a lot of time in the spring creating camaraderie and relationships," said Melvin.
This year the makeover has been a bit drastic. The A's have a completely revamped infield. First baseman Ike Davis came over from the Pirates, second baseman Ben Zobrist from the Rays, third baseman Brett Lawrie from the Blue Jays and rookie shortstop Marcus Semien from the White Sox.
Butler will handle the DH duties, Tyler Clippard, acquired from the Nationals, will be the right-handed setup man and right-hander Jesse Hahn, who came over from the Padres, is on the depth chart as the third starter.
"It's not like we haven't had a rash of turnover before," said Melvin. "We used 50 players in 2012. It took time for everyone to find out where they fit, but they did."
It wasn't easy. The A's were 13 games out of first place at the end of June 2012 with a 37-42 record. But they won 57 of their final 83 games, including a season-ending three-game sweep of the Rangers, allowing them to overtake Texas and win the division by one game.
"We brought in some no-name guys, younger players, and gave them a challenge," said Melvin.
The A's met that challenge that year, just like they have each of the last two years.
And with that history on their side, the A's welcome the challenge of turning a revamped roster into a championship team again.
Tracy Ringolsby is a national columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.