For a guy who has only been with the club for a few days, Jake Lamb is already emerging as a player who could help carry the A’s into the postseason.

Acquired in the wake of Matt Chapman’s season-ending surgery earlier this week, Lamb continued to make an immediate impact in Wednesday’s 3-1 victory over the Rockies at Coors Field. The win shrunk Oakland’s magic number to win the American League West to five.

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After collecting two hits on Wednesday, including an RBI single that provided an important insurance run in the sixth, Lamb is now 5-for-11 with two doubles, a home run and two RBIs through his first three games with the A's.

“Jake’s been big for us,” manager Bob Melvin said. “You get inspired coming to a different team and want to put a good showing early on in a completely different situation than what he was in with not much playing time. It makes you feel like part of the group that much quicker when you contribute right away.”

Lamb, a seven-year veteran who was designated for assignment by the D-backs last Friday, seems to be rejuvenated with a change of scenery. His five hits through three games match his hit total through 18 games with Arizona prior to his release.

“I’ve seen him play for a while now [after] facing him when I was in Milwaukee,” Wednesday's starter, Mike Fiers, said. “Every once in a while, going to a new team kind of brings that lift to you, that new air. Putting on a new jersey could change a bunch of things for a guy. This organization knows the hitter he can be. I’m glad he’s in there producing.”

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Lamb’s RBI single extended Oakland’s lead to two runs and was the clutch hit that had been eluding the club. Going back to Tuesday night’s loss in Colorado, the A’s were 0-for-16 with runners in scoring position to that point. Mark Canha broke a 1-1 tie right before Lamb went to the plate with a run-scoring groundout off Rockies starter Germán Márquez.

Lamb's production has also transformed the bullpen into what sounds like a sheep farm, with relievers belting out animal noises every time he gets on base.

“I think our bullpen is getting a little annoying for other bullpens,” closer Liam Hendriks said. “Every time Jake gets a hit, we just go, ‘Baaaaa!’ We’ve been giving him that from the bullpen. He’s fit in well so far.”

Maybe the A’s can use Lamb’s fresh legs as an energy boost, something they need after finishing a grueling stretch. Thursday’s game was their 16th played over the past 13 days, in a fourth city. Going 9-7 over that span, the A’s will get a much-needed breather in the form of Thursday's off-day before starting a three-game series against the Giants on Friday night at the Coliseum.

“This win was probably as big as any we’ve had this year,” Melvin said. “It’s just a big swing with the games that are left in the season. We went after it pretty hard. Mike was fantastic. All the pitching did a great job, and we did just enough offensively. These guys grinded through a difficult period.”

Hendriks ensured that the flight home from Colorado would be a happy one, taking over for left-hander Jake Diekman with one out in the eighth to record the final five outs for his Major League-leading 13th save of the year.

While a normal five-out save could be tiring, Hendriks had to complete it in the high altitude of Denver, which was not ideal, given his medically diagnosed altitude sickness. He was prescribed medication to help the condition prior to the start of the series and got through the outing strong, retiring five of six batters faced in what was his first appearance since Sept. 10.

“I ended up getting on medication to alleviate it,” Hendriks said. “I pitched in Colorado Springs before and had issues there. But I told BoMel I wanted to pitch today, regardless. Luckily, it came in a save situation, and we were able to finish this road trip off on a high note.”

Hendriks and Diekman finished what was a strong pitching performance all-around that started with Fiers, who limited the Rockies to one run on seven hits and no walks. His 77-pitch outing finished with four strikeouts over six innings.

“He kept those guys in the ballpark, and really, a few of the hits he gave up were just scratch hits, whether it was a bloop or shooting it the other way in the shift,” Melvin said. “He had to work -- you always do here. Throwing 80-something pitches here, it feels more like 100.”

The overall numbers don’t jump out for Fiers -- he now has a 4.67 ERA -- but the results speak for themselves when quantifying his value to the club. He is 6-2 on the year, with the A’s 8-2 on the days he has started.