It is conceivable that three of the four clubs housed in the division will play their way into the postseason, snatching both Wild Card bids under the expanded playoff format.
The Rangers lead the division by three games over the Athletics, who have a 4 1/2-game edge over the Angels. The Mariners are 17 1/2 games behind Texas but only seven games below .500.
The division's overall winning percentage is .548. No other division is even close. In the final season of the current alignment, with the Astros coming aboard the AL West in 2013 to bring balance to the leagues and divisions, the four-pack is flexing its collective muscle with unmatched pitching.
The A's would be leading both the AL East (by a game) and AL Central (by 4 1/2 games). The Angels would lead the Central by a game, and they'd be 3 1/2 games off the pace in the East.
"I think it's the most competitive division in baseball right now," said A's skipper Bob Melvin, a prominent AL Manager of the Year Award candidate.
Mike Scioscia, in his 13th season as Angels manager, has been voicing that opinion for more than a decade -- generally falling on deaf, disbelieving ears.
"Our division is tough, no doubt about it," Scioscia said. "Oakland and Seattle always play us tough, and everyone knows how good Texas is."
History bears out Scioscia's contention. Since his arrival in Anaheim in 2000, the AL West has finished above .500 as a division in 10 of 13 seasons. In 2011, when the AL East was the dominant division, the West had a .498 overall winning percentage.
In 2002, the Angels' magic carpet ride of a season in which they went from Wild Card to World Series champion, the division had a .566 winning percentage. It was also the best in the Majors in '01, at .565.
"To win this division, you need to be good -- consistently good," Scioscia said. "There are no soft touches here. All four teams have had runs where they were as good as anybody in the game. It's been a great division for as long as I've been here, whether people want to believe it or not.
"The A's have caught everyone's attention, but look at how Seattle has played in the second half. You're in for a challenge every time you play a team in this division."
The Mariners appeared on their way to a third consecutive dismal season at the All-Star break with a 36-51 record, but they have rallied with a competitive 34-26 second half.
"They're pretty good," Texas manager Ron Washington said, his Rangers having taken their 11th series in the past 13 with Sunday's win in Seattle. "They've been playing good baseball since the All-Star break.
"They were so far down at the All-Star break that it may not seem to matter, but they have been playing good baseball since the All-Star break against everybody. I knew Eric Wedge would get them going. He's a pretty good manager."
The A's (41-19) have been the division's hottest outfit since the break, with the Rangers (35-25), Mariners and Angels (32-29) all above .500.
Collectively, the four clubs have pounded the AL since the Midsummer Classic at a .589 clip.
For the season, the AL West is running away as a quartet, with its .548 winning percentage. The National League East and AL East both come in at .514. Forming the second division, divisionally speaking, are the NL West (.492), NL Central (.476) and AL Central (.470).
As a certain former president Bill Clinton would say, it's arithmetic.
The consistency and efficiency of the three AL West contenders is underscored by a remarkable achievement. The Rangers, A's and Angels each own winning records at home and on the road and against the AL East, AL Central and NL.
Take away their 19-26 record within the division, and the Mariners are a .500 team against the rest of baseball.
When it was announced that Houston would be coming to the AL West, the familiar response of critics was that a weak division would be getting weaker. On the contrary, the Astros -- burdened with the worst record in the Majors as they prepare to depart the NL Central -- happen to be joining the strongest of the six divisions.
The Rangers, two-time reigning AL champions, and Angels, fortified by a winter free-agent bonanza, were expected to be powerhouses. The surprise of surprises is the emergence of the A's, who came into the season with a nondescript roster and the 29th-lowest payroll in the game, with only the Pirates spending fewer dollars on player personnel.
"Everybody is playing well," Washington said of the AL West. "This division has pitching. All four teams have pitching. If you have pitching, it's going to be competitive. Everybody knows what the Angels have, and the Athletics have always had good pitching. Every year they have guys who can pitch."
The A's and Mariners are second and third, respectively, in team ERA in the AL behind the Rays. The Rangers are fifth, the Angels seventh.
The West is pitching rich, for sure, but it also makes noise offensively.
The Rangers lead the Majors in runs scored, while the Angels are third in the AL, six runs behind the Yankees. Playing in pitcher-friendly ballparks, the A's (11th) and Mariners (last) are not scoring a lot of runs, but their arms are keeping them in games.
Against long odds, the A's are taking the second-best record in the league down the stretch, hoping to turn this into another memorable season in the franchise's rich and unique history.
"It's remarkable what happens when you can pitch like the A's and have players who are letting it hang loose," Angels general manager Jerry Dipoto said. "They have nothing to lose, and they're playing like it. They have no fear. That's how you win."
Despite hitting only .236 as a team with a .307 on-base percentage and .398 slugging mark, the A's have managed to outscore the opposition by 84 runs.
"We feel with our pitching staff, we can compete with any lineup -- and we've proved that so far," said catcher Derek Norris. "It is remarkable that these guys have come in and put up numbers. It's very nice to see."
Four of Melvin's five starters are rookies, and each is performing at an uncommonly-high level. The lone veteran, Brett Anderson, is 4-1 in five starts coming off Tommy John surgery.
The Angels invested heavily in Albert Pujols and C.J. Wilson, intent on overtaking the Rangers. A dismal April put them in a hole, and they've been digging out ever since. It doesn't help that 45 of their games have been played in the toughest division, where they're three games above .500.
The Rangers let Wilson go via free agency and replaced him with Yu Darvish, relying on their power-packed lineup to carry them to the finish line again ahead of the pack.
It has been a struggle, but this is a team of great inner resolve. Texas hasn't assembled the league's best record -- in the sport's toughest division -- on reputation. It's the product of planning and performance.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.