In 2008 the Yankees missed the playoffs and had a hole at first base. They hoped to remedy both that winter by signing Mark Teixeira. Healthy as a horse, Teixeira has delivered homers, RBI and defense as expected and the Yankees have been in postseason all three years he’s been on the squad. They also won their first championship since 2000.

No buyer’s remorse there right? Who’s gonna argue with 111 home runs and 341 RBI in just three years? Two Gold Gloves to boot? A runner-up for MVP? Just keeps getting better and better with big Teix. Until it gets worse.

Yankee fans are shaking in their boots about the rest of Teixeira’s contract and here’s why: it looks like he can’t hit righties anymore, and out of six Postseason series with the team, he’s been dog poop in five of them.

These are not minor quibbles nor inventions of the back pages and call-in radio programs. These are the legit facts. Teixeira’s batting average against righties has fallen from .282 to .244 to .224 in the last three years. And his cumulative postseason triple slash with the Yankees over 123 plate appearances is .170/.276/.302. Eighteen hits in 106 at bats.

The postseason futility is a bummer and not a small reason why the Yanks have been bounced in 2010 and 2011, but it’s not predictive. He might have a good series down the road and help them win another title. And all those games when he didn’t hit, he was out there making some good defensive plays. If he choked because he was scared of the big stage, wouldn’t he be bad in field as well? He sucked, but it’s over

The real concern when it comes to his performance is the decline against righties. Has he hit bottom? Will this trend continue? Will he rebound?

Let’s look at the damage. His overall average has declined from .308 the year before he joined the Yanks to .292 in his stellar 2009 campaign to .256 and skidding down to .244 for a pedestrian-yet-productive-2011. Obviously, the shrinking average indicates Teixeira is trading hits for outs. But let’s try to figure out what’s going on in that exchange.

First thing we have to do is to separate his left-handed stats from his right-handed stats. His right-handed season was excellent – in fact, he’s hit for big power and good averages all three years as a Yankee. That’s no surprise as he has always hit lefties well. He’s hitting more homers, maybe due to Yankee Stadium’s cozy corners, but overall, he’s a carbon copy of the guy the Yanks thought they were getting.

His left-handed stats paint a stark contrast. At first glance, everything looks down from his career norms, and it is, in absolute terms. But diving into the components, we find it’s not that simple. Even as the batting average plummets, Teix is walking and whiffing with the same frequency, and his ISO (SLG – AVG) is also at his career norm. So if he’s turning hits to outs, they are not turning into more strike outs (phew) and the hits themselves are just as powerful as ever.

So where are the hits going? When Mark Teixeira bats left-handed, he often faces a shift – an extreme defensive alignment where the opposing infielders give up ground on the left side of the diamond to overload the right. Teixeira, a pull-hitter from the left side, hits a lot of balls into the shift and very few the other way. He loses some hits to the shift and he’s not making them back by exploiting the vacancy on the right side of the infield.

Could the shift account for most of Teixeira’s troubles against righties? Looking beyond batting average to his average only on balls in play, this theory starts to make some sense. As a left-hander, Teix had a pitiful BABIP of .222 (and only .256 in 2010). For the meat of his career his BABIP has been reliably between .290 and .314. Eureka?

If Teix is the same player he always was, and opposing teams have figured out exactly where to stand to rob him of singles, then the case should be closed. Teix is losing singles from the left side of the plate because of the shift.

But Teix is not exactly the same hitter he always was. The shift is playing a part, and Tyler Kepner cited Yankee research this summer which indicates it’s stealing 20 points off his average from the left side, but it’s not the whole story.

In the last two years Teixeira has seen career highs (or close to them) in O Swing % (the amount of time he swings at pitches outside the strike zone), FB% (the percentage of contact that results in fly balls) and in IFFB% (the percentage of contact resulting in pop ups on the infield). Since we already know his walks and whiffs are not changing, we know that the result of these tendencies is a sacrifice of line drives and ground balls, both of which go for hits more often than fly balls and pop ups.

What kind of balls in play will the shift snare? Mostly ground balls and line drives. Teix is surely losing some hits there, we can see it happen. But since his whole batted ball profile is transitioning away from ground balls and line drives, the shift can’t be solely responsible.

I find it hard to believe teams weren’t shifting on Teix in 2009 or on previous teams. We know Giambi faced shifts before Teix even entered the league, why would the opposition wait until 2010 to try it against Teixeira?

While we can’t be certain, swinging at pitches outside the strike zone sure sounds like a confused hitter, mired in a slump, trying to hack his way out of it. When that hitter swings at pitches outside the strike zone, pitches that are harder to drive with authority, he gets jammed and pops out. He gets under high fast balls and hits towering fly outs. And he yanks outside pitches right into the teeth of a shift.

Frustration leads to desperation. Desperation leads to poor decision-making. And the batting average continues to fall, caught in a negative feedback-loop. It’s possible the pitchers are getting wise as well. In 2011, Teixeira saw a fewer percentage of pitches in the strike zone than ever before. (That must be why the walks stayed the same even though Teix was swinging at slop.)

Teixeira faces a combination of four factors eroding his average from the left side. The shift, hitting more fly balls and pop outs, swinging at bad pitches more often, and of course, some good old fashioned bad luck on balls in play. He can rebound from the bad luck and rededicate himself to not swing at bad pitches.

But if Teixeira wants to hit a respectable average again, he’s going to have to make some alterations. He’ll need to take the ball to all fields to punish the shift when the location of the pitch dictates. He’ll need to revisit film from earlier in his career and try to figure out why he is hitting so many harmless pop outs. He’ll need to exchange those easy outs for liners and hard grounders. Some of those will end up as outs because of the shift, but he needs Kevin Long’s support to ride those out and stick with his new (old) plan.

Jason Giambi had a fine Yankee career. But his .260 batting average was a far cry from the .308 average he brought with him. He had to deal with the shift and injuries and whatever it was that going on and off steroids was doing to him. He never found a way to reclaim those points of batting average after his first year, but he still mashed with homers and walks and was a part of many great offenses.

Teixeira can do all of that minus a few walks and play good defense as well. If the worst case is that Teix is now a .250 hitter, that’s a bummer and he won’t be worth his contract, but he’ll still be good. But from what we’ve seen and heard of the guy, I’m pretty sure he’s not going to be satisfied down there. He’ll work his butt off to improve, and luckily, the Yankees just have to go to fangraphs.com to pinpoint where he needs to direct his attention.

All statistics from fangraphs.com & baseball-reference.com

[Images via nj.com & southernbelle.mlblogs.com]