Adam Eaton hits a single in the first inning against the Los Angeles Dodgers at Camelback Ranch. IMAGE: Matt Kartozian-USA TODAY SportsSports

As you’ve surely heard, Adam Eaton has been shut down with another round of elbow troubles. Kevin Towers has stated that there is no new damage to Eaton’s elbow as revealed by his latest MRI. Instead, there is fluid and swelling around the ligament. As a result, he’s being shut down with a “sprained elbow” for six to eight weeks to rest and build up strength in the joint. Let’s hope this works.

And if you haven’t been following along, although you likely have, this is Eaton’s second bout with elbow trouble this year. Eaton was pegged to be the team’s Opening Day starting centerfielder and had a strong showing in Spring Training until late March when he first experienced discomfort in his elbow. During his rehab stint, Eaton played 16 games in preparation for a return to the desert. In 13 of those games, however, he DH’d, meaning he only played centerfield three times. Those three games, plus whatever activities he was participating in on the side, were enough to cause the injury to flare up again. That should be concerning.

The issue here is not about Eaton specifically, though. It’s about prospects and young players who haven’t exactly proven themselves as quality big league regulars. If there’s anything we can learn from this situation, it’s that nothing should be taken for granted when it comes to roster constructions and counting on certain guys to develop and perform. Every player should be considered a wildcard until further notice.

Throughout the minors, Eaton had been very durable, playing 121 and 130 games in his first two full season, respectively. It’s not as if we should have seen this coming. But while we might not have been expected to see elbow troubles cropping up right as he was about to make his splash into The Show, perhaps we presumed a little much when he was expected to be a strong on-base presence and base-stealing threat for the Dbacks for the next five or six years. In other words, we got ahead of ourselves a little bit and now we have re-examine the amount of faith we put into an unproven commodity. The stats bear themselves out all through the minors and even in his brief major league sample in 2012, but slumps, adjustments and inconsistent performances aren’t the only thing to be worried about with young players as injuries often happen, too.

Adam Eaton during photo day at Salt River Fields. IMAGE: Jake Roth-USA TODAY Sports

It’s easy to fantasize about lineups and defensive positioning, especially in the winter. Let’s face it, it’s better to dream of baseball than just about anything else that time of year. With that said, we easily to get carried away and start projecting things that we aren’t sure about yet. Perhaps this strikes a chord with me because I’ve always been a Mariners fan at heart and we’ve seen disappointment after disappointment (Ackley should be joining Montero in AAA, IMO). Eaton looked like the future (as did numerous Mariners draft picks), but there are some serious variables out there that even the best scouts and talent evaluators can’t see coming. These elbow issues are just another sad example of that.

I hate to see Eaton hurt because I think he could make this Diamondbacks team even better than it currently is. Maybe the rehab works this time, maybe it doesn’t and he eventually needs some kind of surgery. That might kill his throwing arm or force him to adjust his swing. Then again, maybe this is the last bump in the road before a long and prosperous major league career for Adam Eaton. We just don’t know and we shouldn’t presume to.

This situation should serve as a reminder about counting our chickens before they hatch. It should also be an opportunity re-emphasize the importance of solid drafting and international acquisitions because if random events like Eaton’s elbow troubles should be somewhat accounted for when projecting rosters, depth is the most important thing an organization can have. No player, no matter how good or durable they may have been as an amateur or in the minors, should be written into the organization’s future in ink. We have to temper expectations and expect the unexpected until proven otherwise.

Like a Texas Hold ‘Em hand, it’s probably wisest to slow-play player expectations, and the usually durable Adam Eaton should remind us of that.

Jason Kubel prior to the game against the San Diego Padres. IMAGE: Christopher Hanewinckel-USA TODAY Sports

It’s no secret that the Diamondbacks are struggling to score runs. Some of that can be chalked up to their inability to hit with runners in scoring position, but there’s also another culprit: they’re struggling mightily against left-handed pitching.

With Jason Kubel, Gerardo Parra, Didi Gregorius, Miguel Montero, Eric Chavez and Eric Hinske all being left-handed batters, teams have been able to neutralize the Diamondbacks when they put a lefty-starter on the mound. With Adam Eaton set to arrive in Phoenix in the near future and AJ Pollock likely headed back to AAA, that will add another left-handed hitter to the lineup at the cost of a right-handed one.

Against righties, the Diamondbacks rank ninth in the majors with a .754 OPS. Against lefties, they rank 24^th with a .669 OPS. These splits are problematic and will continue to be so unless the team can make some adjustments. Currently, Kubel (.452), Chavez (.333), Hinske (.600), Montero (.657) and Parra (.658) are all struggling against lefties, showing typical platoon splits. Chavez and Hinske are primarily bench bats that face right-handed pitching late in games, but Kubel, Montero and Parra are expected to drive the offense. Gregorius has hit lefties well in his short time with Arizona, but showed some splits in the minors.

The biggest problem lies in the fact that the team doesn’t have a right-handed compliment to Jason Kubel. His only real value to the team is with his bat since his defense rates so poorly. When lefties take the mound, Kubel is effectively neutralized. Adding Adam Eaton into the lineup may soon be able to fix that defensive issue, but it likely won’t help much in terms of offense against left-handed pitching.

Look for the team to perhaps make a move in the near future to acquire a right-handed outfielder or bench bat with power that they feel more comfortable with than Pollock. Eric Hinske isn’t being used much and could be flipped or the team could put together a package around Pollock to obtain a player more to their liking. Selling high on Pollock might be a good idea and while he’s certainly a functional player, he may not be what the organization needs right now.

This team is in a win-now position and may need to do something to remedy this problem sooner rather than later. Triple-slaching .224/.303/.335 against lefties isn’t going to get it done down the line. With starting pitchers like Clayton Kershaw, Madison Bumgarner, Barry Zito, Hyun-Jin Ryu and others likely playing critical roles against the Diamondbacks down the stretch, a strong lineup against lefties is going to be critical. The Dodgers won’t stay in last place forever and the Giants aren’t going anywhere, so improvements must be made. While sample size and slow starts can account for some of the issues, a roster change may be the best solution.

The four outfielders destined to make the Opening Day roster were Cody Ross, Jason Kubel, Adam Eaton and Gerardo Parra. An injury to Ross kept him out for the first 10 games and just when he was ready to return, Kubel went down and has been out for the last 13 games and counting. Eaton hasn’t played at all and is likely still out for two or three more weeks with an elbow strain. In case you aren’t counting along, that leaves Gerardo Parra as the only constant in this equation.

Diamondbacks center fielder Gerardo Parra scores on a single by center fielder A.J. Pollock in San Francisco. Image: Ed Szczepanski

And what a constant he’s been. Through 22 games, he’s hitting .315/.374/.461 primarily from the leadoff spot while continuing to play outstanding outfield defense. His OBP is jumpstarting the offense and he’s scored 15 runs already. Of his 28 hits, he’s racked up eight doubles, a triple and a homer, making good use of his gap power. He’s been the team’s most valuable position player thus far and it’s safe to say that they wouldn’t be battling for first in the division without him.

So what happens when Adam Eaton returns?

We have to assume that Ross will stay in right and Kubel will resume his duties in left when he’s healthy. That leaves centerfield as the only open slot on a regular basis. We’ve seen that Parra can definitely get the job done, but Eaton was supposed to be the new centerfield star before his injury. Assuming that Alfredo Marte and AJ Pollock both head back to the minors once everyone’s healthy, who goes to the bench, Eaton or Parra?

While Parra has been the super-sub the last few years, he’s 26 and hitting his prime. I’m not sure the team can afford to take his bat out of the lineup. Eaton was essentially promised a starting job, but Parra very well may have stolen it from him. Perhaps Eaton becomes the defensive substitute late in games, moving Kubel to the bench and Parra to left when the team has a lead late in games. And given the frail nature of Kubel and Ross, both of whom have missed their share of games to the DL over their careers and aren’t getting any younger, there will likely be starts to pick up along the way for whoever assumes the super-sub role.

We have a few more weeks to monitor this situation, but it’s looming on the horizon and might be the most important roster decision made by that point in time. Unless Parra plays his way out of the lineup between now and then, I can’t imagine Gibby yanking him from the lineup and putting him on the bench in favor of a guy who hasn’t played a regular season game this year. Maybe it’s just me, but Parra is likely the best option for the team in center given what he’s done to date, even when Eaton returns.

Maybe Parra will hit a slump. Maybe Eaton begins the year by hitting .350 when he makes it into the lineup and never looks back. Who knows what the future holds? All we know is what we’ve seen thus far, and thus far, Gerardo Parra has shown that he deserves to be a starter.

*Stats accessed 4/26 via FanGraphs