With an eyes-to-ankles strike zone, mammoth power and uncanny contact ability, Vladimir Guerrero has long made a mockery out of the concept of plate discipline.

From Montreal to L.A., Vlad has never seen a pitch he didn’t think he could hammer. And for the most part, he has been right. Guerrero has a career .397 wOBA, ranking 10th among active players with at least 3,000 PA. The Impaler has the 7th-most Park Adjusted Batting Runs among hitters since 2002. And, he has eclipsed the 30 homer mark eight times.

Are those high-slugging times behind Guerrero, though? Over the last three seasons, Vlad’s wOBA has dipped from .393 in 2007, .373 in 2008 and a mortal .343 in 2009. Guerrero turns 35 this February (we think), and he’s not going to garner a king’s ransom his second time through free agency. Is Vlad still a valuable fantasy option, or is Father Time sapping the free-swinger’s strength?

Much like the original Impaler, Guerrero engendered fear in his opponents. “Fear” is a nebulous term in baseball (see any Jim Rice Hall of Fame discussion), but Guerrero was intentionally walked an average of 26 times per season between 2005 and 2007. That figure dipped to 16 in 2008, and just three in 2009.

Given Vlad’s well-known tendency to hack at balls, strikes, fastballs, breaking stuff, low flying birds and hot dog wrappers, the lack of intentional free passes has led to a plummeting walk rate. Guerrero’s BB% has fallen from 11% in ‘07 to just 4.7% in ‘09.

Want another indication that pitchers are more willing to challenge Guerrero? Take a look at the percentage of pitches thrown to Vlad within the strike zone. As one might expect, pitchers are apt to toss Guerrero a pitch off the plate, considering his expansive strike zone (Vlad has swung at roughly 45% of pitches thrown out of the zone from 2007-2009, compared to the 25% MLB average).

But, those hurlers have thrown him more pitches within the zone recently. Just 32.7% of pitches thrown to Guerrero crossed the plate in 2007. That figure increased to 40.8% in ‘08, and 43% this year. That’s still well below the near-50% MLB average, but it’s a noticeable uptick nonetheless.

Guerrero still creamed the ball in ‘07 and ‘08, with Isolated Power marks of .223 and .218. But extra-base knocks were more scarce this season, with a .164 ISO. Vlad was rarely healthy, serving separate DL stints for a torn pectoral muscle and a left knee strain.

Vlad hit more fly balls in 2009 (near 40%) than in any other season dating back to 2002. But his home run/fly ball rate fell considerably. Guerrero clubbed a homer on 14.5% of his fly balls in 2007 and 16.1% in 2008, but a mild 11.5% in ‘09.

In 2009, Guerrero pulled fewer pitches. And while he hit for far more power than the average right-handed A.L. batter on middle-and-opposite-field pitches in ‘07 and ‘08, that was not the case this past season (numbers courtesy of Baseball-Reference):

Guerrero hit more balls up the middle and to the opposite field, with far less authority than in years past. Was Vlad a little late in catching up with fastballs this year? The numbers suggest that’s the case.

During the course of his career, Guerrero has crushed pitches of all types. It’s really quite remarkable: fastballs (+1.11 runs/100 pitches), sliders (+1.87), cutters (+1.95), curves (+2.78), changeups (+1.95), splitters (+2.93). Heck, he’s even knocked around the knuckleball (+4.85).

In 2009, however, Vlad posted a paltry -0.74 run/100 value against heaters. That was one of the 20 lowest marks among batters with 400+ PA. Guerrero also popped the ball up more often than usual, with a 13.7 infield/fly ball rate (11.2% average since 2002), and he made less contact on pitches within the strike zone (87.1%, 89.1% avg. since ‘02).

The cumulative effect of Guerrero’s injuries has robbed him of the ability to play the outfield (he played the OF just two times in ‘09). This means that he won’t qualify as an outfielder in most leagues. Just as Vlad will only appeal to A.L. teams this winter, his value will be dinged by only qualifying in a “utility” spot in fantasy leagues.

None of this is to suggest that we should stick a fork in Vlad. He surely was hampered by injuries in 2009, as he batted .290/.319/.415 in the first half but a more palatable .300/.347/.498 after the All-Star break.

The problem is, owners just can’t count on Guerrero ever playing pain-free again. It wouldn’t be totally surprising to see Vlad go DH somewhere and rebound somewhat at the plate. But in all likelihood, his days as an elite slugger are coming to a close.