Why the Diamondbacks should not sign James Shields

Speaking yesterday, GM Dave Stewart said the team remain interested in starting pitcher James Shields, though there would appear to be some need to free up payroll, with our figure for 2015, after the signing of Yoan Lopez, coming in at around $106 million, above where the team would like. "I would like to be (under $100 million). I've not been told to be, but I would like to be... I haven't even thought about how. We'll look at the numbers and look at who we'll have to possibly subtract, if that's what we have to do." But would spending big on Shields be a wise investment? I'm distinctly not convinced.

It's too early (for the Diamondbacks)

No matter what comes out of the mouths of Dave Stewart and Tony La Russa, I do not think the Diamondbacks will contend in 2015. Even with the expansion to two wild-cards, this season, you still needed 88 wins to make the National League playoffs, meaning Arizona would need to improve by 24 wins to reach that. No team got so much better in 2014: the biggest increase were the Angels, who were 20 wins better. Now, stranger things have happened - the Red Sox and Indians both showed the necessary level of improvement the previous year - but it would certainly be an exception, not the norm, and should not be planned for.

Based on the moves already this winter, it indeed does not appear the team is planning this way, with the departure of both halves of our Opening Day battery, and no obvious replacements for either man in 2015. While some of the players which have arrived may be used in 2015, I get a clear sense that we are looking further down the line in terms of our next window of genuine contention. Signing Shields now, would most likely mean paying another player on the team an eight-figure sum, effectively as a placeholder, for a season where the odds are against us playing into October.

Philosophically, I think for a mid-budget team like the Diamondbacks, free-agency should be used to fill in gaps of immediate need when the team is ready to contend. It's quite possible that, by the time such a point is reached for Arizona, starting pitching won't be such an area. In the next couple of years, we should be seeing whether Aaron Blair, Archie Bradley, Yoan Lopez, Braden Shipley and Touki Toussaint are the real deal, and that's even discounting anyone on the likely 2015 roster like Rubby de la Rosa. Now, you can never have too much starting pitching, but it might not be long before we have better, certainly cheaper, alternatives to Shields in-house.

Waiting a year would give us a better handle on how our prospects are developing, and whether or not other areas need to be addressed. The Diamondbacks should also then have a significantly increased television deal in place, allowing for greater payroll flexibility without as much need to get creative with backloading deals. And the free-agent pitching class of next winter is likely a higher-quality one, including pitchers younger and possibly better than Shields, such as Johnny Cueto, Zach Greinke, David Price, Jordan Zimmermann and, potentially, Kenta Maeda, if his team decide to post him.

It's too late (for Shields)

Let's assume Shields is signed to a contract that's five years long and costs $90 million; that seems conservative. Roughly, this would indicate a need for him to be worth 18 WAR over that time to make it a reasonable deal. The problem is, over the past five seasons, Shields might not have been worth 18 WAR: the tally comes in at 13.8 bWAR. fWAR is more generous, at he did reach the mark putting up 18.1 fWAR from 2010-2014, but even there, the Steamer projection system has him at three fWAR for 2015. And that's before taking into account aging: Shields had his 33rd birthday last month, so a five-year deal will cover his 33-37 seasons.

How have pitchers that agedfared? Not well. In fact, let's put this in bold, since it's worth emphasizing, as a key point why signing Shields would be a bad idea. No pitcher has put up 18 bWAR over his age 33-37 seasons since Mike Mussina in 2002-2006. The nearest was Andy Pettitte, who reached 17.6 from 2005-2009. Roy Halladay would have had a shot, but retired, having accumulated 17.1 at age 36. I note Mariano Rivera also piled up 17.6. That seems insane, until you realize between 2003 and 2007, he threw 374 innings - basically, two full seasons for a starter - with a sub-two ERA. Also: topping the list post-1976? Curt Schilling and Randy Johnson

So, the chances of Shields being good value for money on any five-year deal are slim. As we noted when his name was first linked to the team in mid-November, the last free-agent pitcher to get a significant contract including his age 37 season, was Derek Loew's four year, $60 million contract with the Braves in January 2009, which didn't work out well for Atlanta at all. When even Kevin Towers thinks long-term contracts for pitchers are a bad thing, you have to believe there's good reason for it, and that may be why Shields is still sitting on the shelf, hoping some team will go the extra season. I just hope it isn't the Diamondbacks.

My opinion hasn't changed significantly since our earlier article. A three-year deal would be what I'd be inclined to offer; four is marginal, and certainly not five. Shields has certainly been solid and reliable over the past four seasons, so the odds are he's not going to turn back into a pumpkin again overnight. But time catches up with everyone eventually, as we found with Bronson Arroyo this season. The trick with starting pitchers is to ride the horse as long as it can gallop, then sell it to somebody else just before its legs fall off. With a 33-year-old pitcher like Shields, even one with a good recent track record of health and effectiveness, the risk seems just too high.