Albert Pujols is on the brink of joining an exclusive group, one he figures to be the last entrant to for quite some time, although several players stand an excellent chance to reach 500.

EDITOR'S NOTE: This story has been updated to reflect the fact that Albert Pujols hit his 600th career home run on Saturday, June 3.

The recent loss of Mike Trout for six to eight weeks due to a thumb ligament injury has threatened to derail the Angels' already slim playoff hopes—just 7% entering Saturday, according to Baseball Prospectus—but Albert Pujols has given Halos fans a good reason to celebrate. On Saturday night, four days after moving to the precipice of history by launching his 599th career home run, the 37-year-old slugger joined the 600 Club with a grand slam in the fourth inning of a 7-2 win against the Twins in Anaheim.

Age, off-season foot surgery and a recent hamstring problem have contributed to a slow start to Pujols' 2017 season, but he's been perking up lately. The homer was his fourth in nine games, a binge that has lifted his season OPS 56 points, from .652 to .708. His overall slash line of .249/.299/.410 is not only a step down from the .265/.323/.469 he's produced since signing with the Angels in December 2011 following an incredible 11-year run in St. Louis, but the on-base and slugging percentages rate as career lows at the moment. Largely confined to designated hitter duty since the start of last season, Pujols' power is his last remaining asset, which is to say that we shouldn't expect much from him as he plays out the remainder of his 10-year, $240 million contract, which runs through 2021.

It's that decline that muted the enthusiasm for his assault on 600. With 445 homers through 2011, his age-31 season, Pujols appeared capable of challenging Barry Bonds' record of 762 homers. Alas, even reaching 700 at this point seems unlikely.

Six hundred homers is rarefied air, albeit not quite as rarified as it used to be. Until Sept. 22, 1969, when Willie Mays hit number 600, the milestone had been reached only by Babe Ruth, who hit his 600th on Aug. 21, 1931. On April 28, 1971, less than two years after Mays, Hank Aaron joined the club en route to toppling Ruth's record of 714 homers, which he did on April 8, 1974. It took more than 31 years for another slugger, namely Bonds, to get there (en route to outhomering Aaron); he did so on Aug. 9, 2002. Since then, Sammy Sosa (June 20, 2007), Ken Griffey Jr. (June 9, 2008), Alex Rodriguez (Aug. 4, 2010) and Jim Thome (Aug. 15, 2011) have reached 600 in comparatively quick succession, doubling the size of the group.

With Pujols, the ranks have now tripled during this millennium, a more drastic expansion than even that of the 500 home run club, which has grown from 16 to 27 in that span. It makes sense to include Mark McGwire, who got to 500 on Aug. 5, 1999, as part of that surge as well, because he, like the other recent 500 club members, benefited from the confluence of factors that pushed per-team-per-game home run rates above 1.0 every year from 1994 to 2009, a level only reached previously in 1987. Smaller ballparks, the changing strike zone, changes to the ball, a dilution of pitching talent due to expansion and the influx of performance-enhancing drug use were often credited (or blamed) for causing that rise, sometimes erroneously; for example, the wave of new ballparks generally had fewer seats but further fence distances, while the growth of the player pool to include Asia as well as Latin America has outstripped the rate of expansion.

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Regardless of what actually caused the rise of home run rates, the prestige of the 500 Club has been diminished in the eyes of many by the number of its members connected to PEDs, namely Bonds, McGwire, Rodriguez, Sosa, David Ortiz, Rafael Palmeiro, Manny Ramirez and Gary Sheffield. The mark, which used to guarantee entry to the Hall of Fame, no longer does. Palmeiro, the first such player to test positive, fell off the ballot after four years, McGwire aged off after 10 years, and both Sosa and Sheffield are languishing with minimal support, destined to fall short of the 75% required for election. Only in the most recent balloting, his fifth year of eligibility, did Bonds reach 50% of the vote, a level that historically has strongly indicated eventual election. If and when he reaches 75%, that will leave Slammin' Sammy and A-Rod (scheduled to join the ballot for the Class of 2022) as the lone 600-level outsiders looking in.

Pujols' arrival at that milestone is worth noting not only because it's an incredible feat but because he's the last player we'll see at that level for awhile. Among active players, the Tigers' Miguel Cabrera (451 career homers), and the Rangers' Adrian Beltre (446) and Carlos Beltran (428) are the only ones above 400. At 34 years old, Cabrera stands an excellent chance to make it to 500. The 38-year-old Beltre, on the other hand, was just activated by Texas on Monday after missing nearly two months with a calf strain, and while he should surpass 3,000 hits later this season (he needs 50), picking up the 54 homers he'll need to reach 500 will be a much taller order. For the 40-year-old Beltran, that milestone is almost certainly unreachable given that he's topped 20 homers only once since 2013.

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Just over two years ago, on the occasion of Pujols surpassing Hall of Famers Ted Williams, Willie McCovey and Frank Thomas to take over sole possession of 18th place on the all-time home run list with 522, I used Baseball Prospectus' rest-of-season and long-term PECOTA forecasts to estimate the number of dingers he and other sluggers would end up with. PECOTA uses recent performance as well as a database of comparable players in terms of age, performance, height and weight to plot out each player's trajectory along an aging curve. Using those forecasts, cutting the latter off either after age 40 (I used 42 last time) or following the player’s first year below replacement level (0.0 WARP, BP's version of WAR), unless their contract runs beyond either of those points, here are the players with at least 200 home runs under their belts who project to hit at least 400 (all numbers through Tuesday):

Player Current HR 2017 age Final HR Albert Pujols 599 37 686 Miguel Cabrera 451 34 651 Edwin Encarnacion 320 34 507 Chris Davis 251 31 504 Adrian Beltre 445 38 497 Giancarlo Stanton 222 27 473 Adam Jones 233 31 440 Carlos Beltran 427 40 439 Ryan Braun 292 33 435 Jay Bruce 253 30 432 Evan Longoria 249 31 421 Nelson Cruz 296 36 418 Jose Bautista 318 36 418 Justin Upton 230 29 416 Robinson Cano 288 34 414 Matt Kemp 249 32 401 Adrian Gonzalez 309 35 401

That's 17 players (out of 37 currently with at least 200), up from 10 the last time around even with the shorter timeframe, thanks in part to the MLB-wide resurgence in home run rates. Where they slipped below 1.0 per team per game in four of the five seasons from 2010 to '14—including 0.86 in the last of those years—they've soared back above that level each year since; the current rate of 1.22 would be a record. In the 2015 set, Pujols projected to finish at 642 and Cabrera at 610.

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Note that the PECOTA projections only run through 2026, which will be Stanton's age-36 season; he appears likely to reach the 500 level if he remains healthy. The other two players whose projections fall short of their age-40 seasons, Bruce and Upton, don't figure to come close to 500 unless they pick up the pace and/or stick around for even longer.

All told, over the next decade that's one more addition to the 600 club and perhaps four who will reach 500 besides Cabrera, though Encarnacion, Davis and Beltre don't have much margin for error. Considering that with Pujols’ next homer, the 2008 to '17 decade will have seen three additions to 600 and seven to 500, that's something of a slowdown. Even with balls flying out of the park, those milestones still mean something.