Blue Jays first baseman Carlos Delgado etched his name in the history books Thursday night with a four-homer game against the Devil Rays, becoming the 15th player to do so. After the game, Toronto GM J.P. Ricciardi speculated that the performance gave his slugger’s MVP candidacy a boost: “Tonight might be the thing that just catapults him in front of everybody else.”

With 41 homers and a league-leading 141 RBI (all stats in this article are through Thursday) — 24 more than the next closest player — to go with his .303 average, Delgado would appear to have the superficially eye-popping stats which impress MVP voters, and a quick peek at his .428 OBP/.592 SLG/1.020 OPS might justify it from the stathead point of view. Of course Alex Rodriguez‘s majors-leading 47 homers, 117 RBI, and .295 might convince voters that this is finally his year, and his .394 OBP/.599 SLG/.993 OPS, not to mention his stellar play at shortstop, could convince a stathead as well. Boston’s Manny Ramirez (.324 AVG/36 HR/102 RBI/.426 OBP/.582 SLG/1.008 OPS) may get a mention, but his disappearing act during the Sox’s three-game series with the Yankees and the subsequent fallout should rightfully doom his candidacy. Some writers might point to the way Shannon Stewart catalyzed the Twins after being traded from the Blue Jays, but as a leadoff hitter with an overall .827 OPS, he doesn’t have the numbers to go very far in a serious discussion. Likewise, we can dismiss Oakland’s Miguel Tejada (.808 OPS), though teammate Eric Chavez (.282/28/99/.350/.508/.858) may get some support.

But one other candidate who’s generated a buzz lately is Yankee catcher Jorge Posada, who’s having the best season of his career. With 29 HR, 98 RBI and a .278 average through Thursday, Posada’s Triple Crown stats are especially respectable for a catcher, and his .404/.509/.913 line can wow the statheads (late note: he hit his 30th HR — tying Yogi Berra for the single-season Yankee catcher record — and topped 100 RBI on Friday). Of course, Posada might have competition from his own team in the form of Jason Giambi (.253 AVG/41 HR/107 RBI/.412 OBP/.532 SLG/.944 OPS) and Alfonso Soriano (.291/36/86/.339/.522/.861). But in a season which saw the Yanks lose three of their best hitters — Derek Jeter, Bernie Williams, and Nick Johnson — to injuries for extended periods of time and saw both Giambi and Soriano alternating feast with famine, Posada’s been the rock in the Yankee lineup. His OPS by month has been between .839 and .995, compared to a 640-point swing for Giambi and a 370-point swing for Soriano. He hasn’t worn down as the season progressed and as most catchers tend to do: a .954 OPS after the All-Star break, compared to .884 before. And unlike the other potential Yankee candidates, he plays a key defensive position, and plays it fairly well. He’s handled a diverse pitching staff through some big ups and downs and drawn praise from every quarter along the way. He’s also taken up the mantle of team leadership, going back to his vocal disgruntlement over the Yanks’ surprising loss in the AL Divisional Series last season to his recent spat with the Devil Rays over beanballs.

The media seems finally to be paying attention to Posada. ESPN’s Joe Morgan kicked off the Posada for MVP campaign last week. He wasn’t particularly lucid, but then that’s Joe Morgan for you:

The Yankees have reached the postseason seven straight years and won four of five World Series from 1996-2000. But in that time, no Yankee won the MVP. If I had a vote — which I don’t — and if the season ended today, that would change. I would give the nod to Posada.

Morgan’s comments did allude to the fact that his pet candidates from a month previous — Giambi and Ichiro Suzuki — had faded, a reminder that it’s a good idea to keep an open mind on this stuff until the playoff races are over.

Locally, some of the New York-area writers have been taking up Posada’s case. Newsday‘s Jon Heyman is skeptical that the writers will get the vote right, period:

Going by recent voting history, we writers will blow it big-time. Posada has been the best and most dependable player on the best team in a most difficult season, a clutch hitter who posted consistent and big numbers while squatting, particularly in the two most telling categories of on-base percentage (.407 before last night) and slugging percentage (.516), an assured leader since the day last October he said aloud what everyone else was too afraid to utter (that the Angels “wanted it more”), a superb handler of a talented but difficult pitching staff and a man with the guts to go nose to nose with Lou Piniella.

One problem is that what Posada generally goes unnoticed. Posada was the steadiest force in a Yankees season marked by turmoil and worry, a tough regular season that culminated with last night’s uncharacteristically trouble-free clincher, a 7-0 whitewashing of the White Sox. Another problem with Posada’s candidacy is that voting writers are too busy making October travel plans to pay attention. My guess? He finishes no better than eighth, and behind four or more players who’ll watch him on TV again this October.

Heyman’s not alone in touting Posada. From New Jersey to Connecticut to Atlanta, he’s got supporters.

Here’s a quick look at some of the more advanced sabermetric indicators. I’ve included a few other candidates, such as Seattle’s Brett Boone and Boston’s Nomar Garciaparra, to round out the discussion:

            RARP    VORP    WS

Rodriguez   76.7    83.4    32

Delgado     68.7    65.1    31

Boone       62.9    70.9    29

Giambi      59.0    56.1    28

Posada      58.5    54.3    27

Soriano     54.5    57.0    27

Ramirez     70.4    66.4    27

Garciaparra 54.7    57.1    25

Tejada      40.7    49.4    25

Chavez      42.2    53.8    24

RARP (Runs Above Replacement Position) is Baseball Prospectus’ stat based on Equivalent Runs, a park-adjusted figure which takes into account the offensive value of a player’s contribution. VORP (Value Over Replacement Player) is Keith Woolner’s similar measure, again using position to measure offensive totals. Neither of these take actual defensive play into account. WS is Win Shares, Bill James’ measure, which DOES take defense into account — a reason I prefer it, though the actual way it measures defensive contribution is certainly controversial. Looking at these, Posada’s case based strictly on the numbers is less than clearcut, even among his own teammates. And he’s well behind hitting machines Delgado and Rodriguez, not to mention Brett Boone.

It’s easy to create a framework around which to justify nearly any of these candidates. But I do think the team’s results should be considered. So in my mind, when it comes to voting on the MVP, playing for a team that’s headed for the postseason isn’t a requirement, but playing for a contender is. That rules out Rodriguez, who led the Rangers to fourth place yet again, and Delgado. Boone is another superficially excellent candidate (.292/34/114/.363/.531/.893), but the Mariners’ drastic fade — which he contributed to with a second-half .792 OPS — makes it tough for me to annoint him the MVP.

That leaves me with Ramirez, a star on the league’s most devastating offensive juggernaut, and three Yankees. And while I’ve got no shortage of bias here, aesthetics do count for something. Manny’s begging out of the Yanks-Sox series, and his reputation for the occasional loaf — not to mention his team’s response to his benching — drives a nail right through his candidacy as far as I’m concerned. Conversely, Posada’s emergence as a leader among the Yanks gives him a little extra juice. Giambi had a good year by anyone’s standards but his own — he’s lost out in the MVP sweepstakes with considerably better seasons than this. Soriano’s low OBP simply hampers him in these discussions like a ball and chain. So for my nickel, I’d give Posada my MVP vote.

I’ll have a more comprehensive look at the awards sometime in the next few weeks.