SURPRISE, Ariz. -- When spring training officially begins Wednesday, the Rangers will trot out the best 1-2 punch they've ever had to start a year in Cole Hamels and Yu Darvish.

All comments about last year's playoffs aside, this is the Rangers' best asset and their biggest advantage. It is the best 1-2 combo in the AL West and probably only behind Boston, and not by much, in the whole of the American League. It is what they've always hoped for.

And now that we've got the season preview out of the way, it's time for the next question: Is it one and done?

Early appearances: It certainly looks that way.

Darvish will be a free agent after the season. Though he's amenable to discussing a contract, there has been little in the way of actual conversation with the front office this winter. On its own that doesn't mean something can't get done; general manager Jon Daniels has a decade-long history of negotiating extensions during spring training (see Michael Young, Ian Kinsler, Elvis Andrus and Adrian Beltre, to name four).

However, a Darvish deal would be a bigger financial investment than anything that's come before in the matter of spring talks -- something in the $150 million (or more) neighborhood. Likely more complicated, too. Pitching deals always are. It might have to include an opt-out clause, insurance policies and other gizmos to be workable for both sides. It is fair to think that such a deal might require a little longer to negotiate than others.

Which begs this question: Why hasn't more been done?

About this we can only theorize, as Daniels doesn't discuss contract negotiations.

There are three theories here:

1) They have other ideas

Originally, I wrote this as "they aren't interested" in him. That would be harsh. What's not to like about Darvish when he pitches? By almost any advanced pitching metric, he ranks among the best in baseball over the course of his career.

In fielding independent pitching (which aims to measure a pitcher's effectiveness on only things he can theoretically control), he ranks 10th; the guys ahead of him have combined for seven of the 10 Cy Youngs awarded during his career. In ERA+ (which adjusts for park and league factors), he is sixth.

The biggest issue is durability. He's averaged only 160 innings over the four seasons he's pitched, and he missed an entire season after undergoing Tommy John surgery. He's going to turn 31 during the season, which is usually considered late in a pitcher's prime to become more durable.

It would kind of make a team long for a younger version of Darvish. And there just happens to be one: Shohei Otani, who currently pitches and hits for the Nippon Ham Fighters (the same Japanese club for which Darvish pitched). Otani is 22, which is younger, for sure. But unless MLB changes its rules, he's so young, teams would have to pay a ridiculous tax to sign him because of the limits of international bonus pools. Early in the offseason, it looked like he was coming to the U.S. for 2018; now it's much more uncertain.

2) They are taking a wait-and-see approach

Without a full season since 2013 (his only 200-inning season in the majors), the Rangers could watch him early and make a pitch at, say, the All-Star break. The problem with this: If he is dominant Darvish, he will be only three months away from free agency at that point and will have all the leverage in the world.

On the other hand, if the Rangers don't contend, they could possibly flip Darvish at the deadline to accelerate a quick retooling process.

3) They can't afford him

Perhaps the weight of contractual obligations to Prince Fielder, Shin-Soo Choo and Elvis Andrus have dissuaded the Rangers from megadeals.

If so, that means they won't be players for any big-time starting pitcher in the offseason, which would leave them with Cole Hamels and Martin Perez and anybody that develops this season under control for 2018. That's a nice nucleus, but it hardly rounds out a rotation.

If they intend to contend in 2018, they'd have to add a No. 1 or No. 2 pitcher. They already have that in Darvish.

Considering how long and hard the Rangers have searched for that quality of pitcher, it might make sense to hold on to what they already have.

On the plus side

Among pitchers with at least 600 innings pitches since 2012, MLB's top six pitchers in ERA+, which attempts to adjust ERA for park and league factors (a mark of 100 is considered league average):

Twitter: @Evan_P_Grant