Aging sluggers and second-half stamina

Mark Teixeira had 508 plate appearances last season, but he was worth just 0.3 WARP. He had 14 doubles and 22 home runs. At 34, he was two full seasons removed from his last good showing, and injuries were piling up. That was nothing, though, next to what Alex Rodriguez was up against. Suspensions and hip injuries stole all but a sliver of 2013 and 2014 from Rodriguez, and Rodriguez is five years Teixeira'€™s senior. Both contracts looked like albatrosses for the aging Yankees, and it looked like New York was headed straight for a multi-year stay in the AL East cellar.

You'€™re probably already well aware of this, but that hasn't happened. In fact, Rodriguez and Teixeira are the backbone of this first-place Yankee club. Teixeira has more doubles and more homers this season than he had last year, in 150 fewer trips to the plate. Rodriguez'€™s 19 homers are already more than he hit in any season from 2011-14, and both his on-base percentage and his slugging average would be his highest since 2009.

Resurgent seasons from Brian McCann and Brett Gardner have helped, but the oxygen fueling the Yankees'€™ offensive fire is the stellar production they'€™ve gotten from their two old sluggers. Teixeira and Rodriguez already have accounted for 4.4 WARP this year; they were worth 0.9 WARP combined in 2013 and 2014. The Yankees'€™ entire division lead (or roughly that) can be chalked up to the surprising dominance of Rodriguez and Teixeira.

It'€™s worthwhile, though, to put what the pair is doing in some historical context because that will help answer a question on which hinges the rest of the Yankees'€™ season: Can they keep it up?

Where they stand

Rodriguez has a 147 OPS+, meaning a league-average hitter would be about 47 percent worse than he has been, given the same mix of park factors. Teixeira'€™s OPS+ is 146, meaning he'€™s been almost equally great. This from two players who each went two straight seasons without providing any significant value, and who are 39 and 35 years old, respectively.

Using Baseball-Reference'€™s Play Index, I dug up the 200 best seasons by players 35 years old or older, since 1969. (I used 350 plate appearances as a minimum threshold.) Through Sunday, Rodriguez'€™s 147 OPS+ would place him 55th on that list; Teixeira'€™s would place him 60th. As you might imagine, though, most of the list is made up of guys who had been good the year (or two, or three, or 12) before, too. Any list of the best hitters at a given age will be made up mostly of Hall of Famers, but if anything, a list focusing on great hitters at such advanced ages intensifies that effect. Because of that, we'€™re looking mostly at lists of players having their last great seasons, but who were very good in the years both leading up to and moving past that campaign.

Thus, I went through and looked for truer comps: players who had two lost (or, at least, significantly substandard) seasons immediately preceding their last hurrah. There are four players I could identify as meeting that criterion, while also hitting well enough to really be on par with Rodriguez and Teixeira. Let'€™s talk about them.

Cal Ripken Jr., 1999 (38 years old): .340/.368/.584, 354 PA

Keeping The Streak going had worn the once-great Ripken down to nothing by the end of 1998. He'€™d been a below-average hitter in both 1997 and 1998, even as he moved from shortstop to third base to lighten his defensive burden. It'€™s unnatural for a player of that age to play anywhere near as often as Ripken did, and despite his best efforts, he couldn'€™t overcome that.

Embracing the life of a normal, mortal player did him good, though. He missed three weeks in April and May, then all of August, but when he was on the field, he absolutely raked. It was his last great season, but it was a refreshing reminder of what Ripken had been, at his peak. On the other hand, he batted fewer times all season than each of Rodriguez and Teixeira has already, so he doesn'€™t provide any particular reason for Yankees fans to hope their sluggers can keep up the pace.

Rickey Henderson, 1999 (40 years old): .315/.423/.466, 526 PA

Henderson had been merely average at the plate in 1997, and a bit worse than that in 1998. He played a lot and remained a remarkable physical specimen. He even led the league in walks and steals in 1998. He just seemed not to have the same quickness, the same electricity in his swing. It seemed all he could do anymore was work walks and run the bases.

In 1999, though, that pop came back. Henderson posted his best BABIP since 1981, his best batting average since 1990, and his best isolated power since 1993. Some of that (the BABIP, especially) is luck, noise over a modest sample. Some of it, though, was Henderson truly rediscovering something, using one last window of good health to find a swing that resulted in the consistent sharp contact he'€™d been missing for the previous two years.

Kirk Gibson, 1994 (37 years old): .276/.358/.548, 382 PA

It'€™s funny that the indelible image of Gibson is that home run he hit in the 1988 World Series. He was hobbled, he was grizzled, and he looked like he was 40 years old. He wasn'€™t, though. That was a 31-year-old Gibson, enjoying the last moment of greatness he would have for a half-decade or so. From 1989-1993, Gibson was limited to 424 games and 1,705 plate appearances, and he hit just .242/.332/.400, bouncing to four different teams.

For much of April 1994, it looked like it would be more of the same, and like Gibson'€™s career might finally be over. Through 20 games, the Tigers were 6-14, and Gibson was hitting .204/.310/.367 in 58 plate appearances. Not even fairly frequent rest was helping him stay healthy and find a rhythm.

Then came three games that changed the story. It began on Friday, April 29, when Gibson hit a two-run triple in the sixth inning that gave the Tigers a lead for good. After a rainout the next day, Gibson began May by mashing a three-run, two-out homer in the third inning of what turned into a blowout win over the White Sox. He was on the bench the next night, as the Rangers came to town, but with one out and two on in the 10th inning, Sparky Anderson called on Gibson to pinch-hit, down by one run. He cracked a three-run walk-off homer. From that point until the strike -- €”not even counting those three great games -- €”Gibson hit .282/.361/.553. It wasn'€™t a full season and it didn'€™t mean much since the Tigers remained terrible, but Gibson's short-lived renaissance was real.

Marlon Byrd, 2013 (35 years old): .291/.336/.511, 579 PA

Byrd, like Rodriguez, lost both time and esteem to a PED suspension in the years leading up to his late-career breakout. He also had injury problems, but the main issue was that, despite his stocky, strong build, he had the swing of a slap-hitting speedster. There was virtually no stride: He would simply throw his hands at the ball, almost from a complete stop.

When Byrd latched on with the Mets in 2013, though, he committed himself to making some real damage at the plate, and it worked brilliantly. Two years later, Byrd keeps raking, not worrying about strikeouts (they'€™re a huge part of his game now, but they'€™re more than offset by all that power) or walks (swinging a lot, especially from the heels as Byrd does, has reduced his walk rate significantly) -- just hitting the ball hard. There's no better model for what Yankees fans can fairly hope to get from Rodriguez and Teixeira going forward.

Can the Bash Brothers keep it up?

You don'€™t need me to tell you that Rodriguez and Teixeira sustaining this level of performance is unlikely. It'€™s incredibly unlikely. Two years of nothing followed by a season this good is exceedingly rare, and there'€™s not much evidence (though there is some, as we've seen) that it will hold up. If and when the fountain of youth in the home clubhouse at Yankee Stadium runs dry, the team is going to need continued good work from the likes of McCann, Gardner and Jacoby Ellsbury, plus a bit more from Chase Headley, in order to stay afloat. The odds of those things happening are better, though all of the players I just named are also 30 or older.

If the Yankees believe Rodriguez and Teixeira will stay healthy and keep up this pace of production throughout the second half, they should be aggressive buyers at the trade deadline. This might be their best shot at an AL East title for four or five years, if only because the competition for that title is fairly soft just now, and is unlikely to be in the future. In truth, though, this remains a flawed, thin, old team, and it will take a rare level of enduring excellence from their two old stars to keep outrunning Father Time, let alone the Blue Jays, Rays and Orioles.