OAKLAND -- The 2017 season was a time of transition for the A's, who made promises of a rebuild and better days ahead amid a third consecutive last-place division finish.
A sluggish start prompted the club to give the young guys a shot, and they responded with a 36-37 record in the second half, finishing on a 17-7 run with a core of baby-faced hitters who are igniting a roster renovation.
Along the way, key moments emerged. MLB.com has recapped the most noteworthy:
Chapman promoted
Third baseman Matt Chapman, the A's first-round Draft pick in 2014, was called on to make his Major League debut June 15, drawing a start against the Yankees in front of a home crowd at the Coliseum and signaling the start of a youth movement that would come to define the A's 2017 season. Chapman held his own at the plate, belting 14 home runs and compiling 40 RBIs in 84 games, but he awed at the hot corner, establishing himself as one of the game's brightest young defensive players -- and as a cornerstone for a rebuilding franchise.

A's reel in three prospects for Gray
When pulling the trigger on a deal that sent Sonny Gray to the Yankees at the non-waiver Trade Deadline, the A's plucked from one of the deepest farm systems in the game, landing center fielder Dustin Fowler, speedy infielder Jorge Mateo and right-hander James Kaprielian. In Fowler the A's believe they have their center fielder of the future, beginning in 2018. Mateo hasn't stopped hitting since landing the A's system, closing the season with Double-A Midland, and Kaprielian -- a first-round Draft pick of the Yankees in 2015 -- is on the mend from Tommy John surgery. The A's expect him to continue developing as a frontline starting pitcher once healthy.
Rallying in Anaheim
The heart of this young team burst open under a hot sun in Anaheim, the A's erasing a five-run deficit and rallying for six unanswered runs for a wild 11-10 win at Angel Stadium on Aug. 6. Several rookies were vital to the comeback, notably Chad Pinder, who collected a career-high four hits. The Angels took a 10-5 lead into the seventh, but Pinder homered, and the A's proceeded to tack on five more runs in the eighth, all with two outs. Khris Davis launched a two-run homer, and the A's kept at it with RBI hits from Pinder and Bruce Maxwell. The drama continued in the home half of the frame, when Santiago Casilla survived a bases-loaded jam to keep the one-run lead intact. A's manager Bob Melvin deemed it "a really good team win."

Olson goes bonkers
Rookie first baseman Matt Olson made homering a daily habit in September, earning widespread attention during a stretch that saw him go deep in five consecutive games for a franchise rookie record. Olson also became the first player in franchise history with 15 home runs in a 21-game span, counting off 16 in a 23-game stretch from Aug. 27-Sept. 22. His 23 home runs in his first 66 games are most by any A's player: Mark McGwire had 22 and Jose Canseco tallied 16. Olson finished with 24 in just 59 games, tying for fourth overall in American League Rookie of the Year voting.

New stadium in limbo
The A's are headed back to the drawing board after plans to build a privately financed ballpark near Oakland's Laney College abruptly derailed. Club president Dave Kaval was expected to spend much of the next year negotiating with the Peralta Community College District to purchase the land he had deemed best fit for a new ballpark, but the governing board of trustees ordered the chancellor to discontinue conversations with the A's, who have yet to announce their next step. They've played at the Coliseum since 1968.