The Los Angeles Angels’ best player, Vladimir Guerrero, has struggled all season. John Lackey and Kelvim Escobar, both Cy Young-caliber pitchers last year, started the season on the disabled list and have already missed more than three months on the DL combined. The infield has likewise been decimated by injuries throughout the year.

Yet somehow, the Angels have the best record in the American League: They’re in the driver’s seat to win their fourth division title in five seasons.

You can credit a number of factors for the Angels’ success. They’ve shown a flair for the dramatic, racking up a number of walk-off wins. Unheralded players have taken big steps forward, especially on the pitching side.

But in the end, the Angels’ success this season largely boils down to one explanation: They’ve been really, really lucky.

Are you done chucking thunder sticks at me, Anaheimaniacs? Allow me to explain.

Through Sunday, the Angels’ record stood at 39-25. Yet the team averages 4.2 runs scored and 4.1 runs against per game. Those totals, extrapolated evenly over 64 games, would work out to a 33-31 record under normal, neutral circumstances. That means the Angels have won six more games than you’d typically expect from a team with those run-scoring and run-preventing abilities.

So, how does a team win so many more games than you’d expect? Getting blown out a lot can skew the numbers. The Angels are 3-7 in games decided by five runs or more — that record includes a 14-2 lambasting at the hands of the A’s on April 28. Such lopsided losses have an especially big effect on expected records early in a season, when we haven’t processed enough game results to smooth out those kinds of blowouts. But over the long haul, good teams tend to blow out their opponents more than they get blown out.

On the flip side, winning close games can help a team look like overachievers. Through Sunday, the Angels were 13-8 in one-run games, the best such mark in the American League. They’ve been especially adept at racking up walk-off wins. When the Angels beat the Jays 4-3 in their last at bat on June 1, that marked the fourth time they’d delivered a last-AB win in a six-game stretch. In that June 1 game, the winning run was scored when Jays closer B.J. Ryan plunked Angels second baseman Howie Kendrick with the bases loaded, knocking in the winning run.

It’s tough to chalk up a game-winning HBP to anything other than luck (or at least bad aim on Ryan’s part). The larger question, though, is whether a team that wins a disproportionately large number of close games does so because of some special skill set — a team-wide ability to come through in the clutch — or just luck.

The 2007 Arizona Diamondbacks offer an interesting case study. Coming off a dreary 76-86 season, many mainstream baseball writers picked Arizona to have another mediocre-or-worse season. Instead, the D-backs surged to a 90-72 record, winning the NL West. The team went 32-20 in one-run games and lost its share of blowouts — so much so, in fact, that Arizona actually scored fewer runs than it allowed. The team’s expected record was just 79-83, meaning the D-backs had outperformed their expected record by an astounding 11 games.

An astute manager and a strong bullpen can both help a team win close games and do better than you’d otherwise expect. That was the case for Arizona, as manager Bob Melvin quickly identified his best relievers last season and gave them almost all of the team’s high-leverage innings.

The Angels share some of those same traits. Though he’s not quite as dominant as he’s been in years past, Francisco Rodriguez provides a strong anchor for the Angels’ bullpen. Manager Mike Scioscia recently tapped rookie reliever Jose Arredondo to handle the team’s setup duties. The 24-year-old has rewarded his manager with 11.2 lights-out innings, yielding just seven hits and no walks and striking out eight as a bridge to K-Rod.

Other young players are also having breakout seasons. Previously unknown Joe Saunders is a leading candidate to start the All-Star Game, with a 9-2 record and a 2.63 ERA. Ervin Santana, a talented but wildly erratic pitcher who’s looked unbeatable at home and piñata-esque on the road, is 8-2 with a 3.01 ERA thanks to more balanced home/road splits this season. With Lackey now back in the rotation, Escobar and speedy on-base threat Chone Figgins on the mend, and Guerrero likely to start hitting sooner or later, there’s reason to expect improvement too.

Still, there’s no getting around the luck factor. Even Saunders’s success is largely built around a .238 batting average allowed on balls in play. That’s the fifth-lowest mark in the majors, well below typical league averages around .300, and more likely the result of luck than skill given what we know about pitchers’ ability to control the results of a ball in play (for the most part, they have very little control).

The Angels may well need that luck to last, given the shaky state of their offense. Normally, the team has enough firepower to overcome the flaccid bat of Garret Anderson in a corner outfield spot. But subpar numbers from the rest of the outfield and the team’s shortstop combo of Maicer Izturis and Erick Aybar make it that much tougher to carry Anderson’s putrid .298 on base percentage and .386 slugging average. The team seems to make the playoffs every year, go into the postseason looking like they’re a big bat short of being a real World Series contender, and prove that point with a first-round exit. We may get a repeat performance this year.

That’s assuming the AL West’s second-best on-paper team wins the division, though. The second-place A’s, who trailed the Angels by 4.5 games through Sunday, sport an expected record of 36-27. That’s 3.5 games better than what the Angels’ expected mark, but also two games better than the A’s actual record, a more pedestrian 34-29.

That’s right. Apparently the Angels are so lucky, they can even will their arch rivals to lose more games than they should.

Mr. Keri (jonahkeri@gmail.com) is a writer for ESPN.com’s Page 2.