Yesterday, the Los Angeles Angels scored the coup of the pre-deadline trade market when they acquired slugging first baseman and free agent-to-be Mark Teixeira from the Atlanta Braves in exchange for first baseman Casey Kotchman and minor league pitcher Stephen Marek. Teixeira brings the Angels a career .286 AVG/.373 OBA/.536 SLG line with power from both sides of the plate and a four-year record of hitting 30 or more home runs.

From both ends, the trade is a victory for realistic self-appraisal and a defeat for complacency. For the Braves, the trade is a gesture of surrender in the pursuit of what has been a wide-open National League East. For the Angels, it represents the understanding that despite baseball’s best record, the team isn’t nearly as good as it appears to be.

With a .619 winning percentage through Monday, the Angels are on a pace for 100 wins, the traditional mark for excellence in teams. They lead the American League West by 11.5 games with 57 games to go. The Angels’ lead is not insurmountable, but it’s the closest thing there is to safe in the majors. Barring a 2007 Mets-like collapse, the Angels will be in the postseason — and the Angels have enough minor league depth that they can survive key injuries in the way the Mets could not.

Yet, the Mets’ fall out of the postseason, as well as their own chances of succeeding if they reach the postseason, had to motivate this trade, because as strong as the Angels’ record is, it reflects too generously on a team that has had a great deal of luck. A dominating team normally has its share of dominating performances. The Angels don’t have that. Offensively, they rank in the bottom half of the league in runs scored per game. The offense is eighth in runs scored, 11th in on-base average, 10th in slugging percentage. The declining Vladimir Guerrero is hitting .287 AVG/.350 OBP/.484 SLG, numbers that have more in common with the declining Bobby Abreu than any current MVP candidate. Chone Figgins is having the worst season of his career. Mike Napoli has been hurt, leaving catching in the hands of non-hitter Jeff Mathis. Garrett Anderson and Gary Matthews have been almost total losses.

The offense, then, has boiled down to the good-not-great Guerrero; Howie Kendrick’s imitation of a Robbie Cano season, interrupted by injury; Torii Hunter, who is having one of his best years without being a threat to any of the league leaders, and the now-departed Kotchman, who has been up and down, mostly down, having seemingly lost his ability to control the strike zone.

The pitching staff, taken as a whole, has been solidly above average, but ranks just fifth in the league in runs allowed per game. Strikeouts are key to succeeding in the postseason — if David Ortiz doesn’t put the ball in play, it can’t go out of the park — and the Angels aren’t the best at getting those, ranking ninth in the league in that category. Ervin Santana and John Lackey can dominate at times (last night Lackey missed a no-hitter in Boston by two outs), but Jered Weaver has been uneven, and Joe Saunders and Jon Garland are the kind of pitch-to-contact types who can really get undressed by a top offense.

Given the basically average overall performance of the Angels’ roster, if you didn’t know their record, there would be no reason to guess that they were on a 100-win pace. Their expected won-lost record, based on runs scored and allowed, is only 57-48, a pace for 88 wins. That’s not good enough to win the wild card in most seasons, and it strongly suggests that, as the old song goes, the Angels are building up to an awful letdown, be it through a sudden Mets-style change of luck or simply through running into a team that’s actually as good as its record in October. Most teams do not exceed their projected records by eight wins in the course of a season, and for the Angels to have expected that they would continue to do so would have been a supreme act of unearned egotism and misplaced self-confidence.

The Teixeira trade shows that the Angels aren’t fooling themselves. They add a patient, powerful, middle-of-the-order bat they have been missing all season, a switch-hitter who also happens to be a Gold Glove defender at first base. Teixeira will be worth a couple of extra wins to the Angels for the rest of the season beyond what Kotchman would have contributed (Kotchman is also a good fielder). That said, he doesn’t solve all of their problems — a left fielder, slugging catcher, or shortstop with a bit more pop would have more directly addressed their needs. Still, Teixeira was without a doubt the best player on the market, he cost them little — a first baseman who hadn’t developed into a star, and a Double-A righty middle reliever, baseball’s most fungible brand of prospect.

The Angels still might not be the team they’ve pretended to be, but they just took a step closer to merging their record and their reality.

Mr. Goldman writes the Pinstriped Bible for yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.