I'm writing this a little ahead of time because I'm in the process of moving this weekend so I won't have the luxury of waiting until after the game on Thursday night.  If something tremendous -- positive or negative -- happened in last night's game, feel free to talk about it; it's not a lack of interest on my part, it's the impingement of the real world on my hobbies.

At the beginning of the season, not many people truly believed the Cardinals would be contenders in the NL Central.  PECOTA had the Cardinals coming in a distant 4th in the division with a negative run differential.  They're currently a game back of Chicago with the 5th best run differential in the NL.  I'm curious what kind of off-the-record conversations the front office had for expectations -- whether they really truly believed (or their metrics/analysis told them) that they were going to contend.  Apparently the team thought that they were close enough to contending that they didn't need a full blown rebuilding process and everyone toed the line accordingly during the offseason and Spring Training.  I would have defended them if they had gone into a rebuilding process; instead, they really are contending and regardless of whether or not they truly expected to before the season began, now would be a good time to decided if contention is enough or if they're really committed to winning the Central.

I'd be disingenuous if I claimed that I've been mulling over this idea that I'm about to present for a while.  I haven't.  A commenter (mikedallas45) asked a question in Nate Silver's chat over at BP the other day about Brian Roberts.  Nate responded that the upgrade could be sizable given the players that the Cardinals are currently using at second base.  I've made no secret of my distaste for the Cardinals primary second baseman (Aaron Miles, Adam Kennedy) in terms of what they provide on the field for the team.  Subjective opinions aside, if the Cardinals are going to upgrade the team, 2nd base is the logical place to do it and Brian Roberts would seem to be a prime target.  I can't recall a time since Larry Walker that the Cardinals made a move in season that I would perceive to have as much impact as a potential Brian Roberts trade -- but lets run the numbers to find out.

In a weekend when I wasn't moving, I'd be breaking out my spreadsheets to run wOBAs and find the averages for the league and calculating runs above average per plate appearance.  Since I don't live in that world though, I'm going to use VORP, which is handy in that the math is done for me, and while I prefer wOBA, the differences shouldn't prevent us from getting an estimate of about +/- .5 wins.  Let's assume that the acquisition of a second baseman would suddenly bring the manager and front office to their collective senses and we'd no longer need 4 middle infielders on the roster -- in fact, let's say they do away with Aaron Miles and Adam Kennedy.  I know I'm wishcasting here but what the hell.

Aaron Miles has been serviceable as a hitter this season.  I still don't like his skillset -- and once that BABIP regresses about 30 points, he's going to be about replacement level.  That said, he's contributed 2.7 runs per VORP over 113 ABs.  Extrapolate over the season and he's probably worth about 1 win with the bat assuming he maintains that.  That would easily be the best VORP he's posted but benefit of the doubt and all.  Adam Kennedy on the other hand has been his exact inverse.  He's been worth -2.5 runs over 140 ABs.  Together, they're a wash.

Defensively, Aaron Miles is about a -10 fielder (over a full season) according to the defensive metrics -- I'm looking at UZR, RZR and SFR to get an estimate.  Kennedy was beloved by the defensive metrics prior to 2006 with his defense being worth around a win all by itself. 2006 saw him tank across the board and 2007 was only marginally better.  RZR likes him so far this season but I'm more inclined to go with the previous two years worth of data.  He just had knee surgery and I just don't see his defense as a strong selling point anymore.  We'll split the difference and call him a neutral fielder.  What I'm getting at in these last two paragraphs is that Miles and Kennedy at second represent the essence of replacement level.  You should be able to go out and find some player in the minors and approximate their value on the field.  In fact, the Cardinals have such a player named Brendan Ryan but a 3-year contract and some unknown leverage have kept Kennedy and Miles on the team.

To preface the discussion of Brian Roberts, I want to say that I'm leery of 2nd baseman once they hit 30 ; it's a steep decline, on balance, after that age.  PECOTA, prior to the season, expected him to maintain his value reasonably well through age 34.  He's hitting a touch under his preseason prediction at the moment.  PECOTA pegged him at .285/.366/.440 prior to the season and he's hitting .271/.357/.427 thus far.  In 221 ABs, he's produced 12.5 runs.  He's about  30 run above replacement level offensively.  The defensive metrics are a bit mixed -- some like him as a bit above average others as a neutral fielder. 

If you take a look at the Cardinals VORP data thus far this season, Pujols and Ludwick are carrying the offense with Ankiel making a solid contribution.  Outside of those three players, there's no other standout offensive player.  The rest of the team is basically playing slightly above average offensively with no one on the roster being a tremendous dead weight.  Brian Roberts would go a long way to solving that problem.  He'd become the Cardinals 3rd or 4th best hitter and an ideal leadoff man given his OBP and speed on the base paths.  (I'm not totally discounting the value of his running skills but they pale in comparison to his offense.  He might be worth 2-3 runs on the base paths.  I'd rather just be conservative and assume he's neutral.)

It's hard to navigate the tumultuous waters of dealing with the Orioles and Peter Angelos but needless to say, a nice package of prospects would be needed.  They wouldn't be interested in Bryan Anderson but a stab in the dark would be something resembling Jaime Garcia/Anthony Reyes, Chris Duncan/Joe Mather and Jason Motte/Chris Perez.  It's a lesser package than what they got for Erik Bedard but I'd guess that the Orioles would target those players (after being told that Colby Rasmus was unavailable).  It's certainly debatable whether those prospects are worth more than Roberts over the next 5 years but Roberts almost certainly adds more marginal value to the team than losing those players/prospects would cost in 2008 alone.

Regardless of the fine details, Roberts would represent a significant upgrade on the order of 3-4 wins depending on how optimistic you're feeling.  Glancing at the standings, the teams relegated to the cellar currently don't have players that would be worth pursuing.  (If the Athletics fall out of the race, Mark Ellis is another name that would be interesting coming in around 2 wins above replacement. That could take time though where the Orioles are more like to be sellers now.)  Baltimore is the best target even if it's traditionally a difficult trading partner.  The point is that there's no time like the present to upgrade the team.  There's no great -- heck, there's not even a good -- internal solution to the middle infield and the Cardinals have the capacity to really improve the team to keep pace with the Cubs. In the end, it's less a question of if the Cardinals will contend and more one of for how long.