The Braves have acquired Trevor Cahill and cash for their Josh Elander, a 24-year-old former catcher that was playing outfield in High-A Lynchburg for the second time last year. So mostly this transaction is about the Braves getting a cheap starter on the cheap. The quality of that incoming pitcher, and the fit on a rebuilding team — these are the things that are most debatable about the deal.

Like with Nick Markakis before him, the acquisition of Cahill may seem strange for a team that traded away two of its three best hitters for prospects and young pitchers in the offseason. Even with Markakis, the Braves are projected for the league’s worst offense, and Cahill won’t help there either. Even if he’ll help on the other side of the ledger — ZiPs projects Cahill to be worth about a win above replacement — it won’t be enough. Maybe you can make a case that anything can happen in a year, but the Wild Card possibilities for a team projected for 74 wins (maybe 75) aren’t something you bet $6 million on.

Could this be about year two? Like Markakis, Cahill could be kept in the fold in 2016. He has a $13 million option, and maybe by then things will be building again instead of tearing down. Freddie Freeman, Andrelton Simmons, Shelby Miller, and Alex Wood will all still be reasonably-priced and decent. The system will be graduating third baseman Rio Ruiz, second baseman Jose Peraza, catcher Christian Bethancourt, and a host of pitchers sometime over the next two years. If Cahill can be glue, maybe the 2016 Braves will be projected close enough to .500 to start thinking about improving around the edges in case a wild card run happens.

Could Cahill be worth that $13 million? Will the pitcher who lost his rotation spot last year be worth one this year?

That might be the harder question to answer, considering the fact that if a team thinks that Nick Markakis and Trevor Cahill are values at their prices, they should probably go get them, even if the team isn’t considered a contender from the outside. And Cahill has changed enough over the years to make this question a tough one to answer.

From 2010 to 2013, we knew who Trevor Cahill was. Dude was about ground balls. He had a top-five grounder rate (57.3%), but was underwhelming when it came to strikeouts (17.6%) or whiffs (7.6%) or velocity (89.5 mph average fastball velocity). He was also about a league-average pitcher most of those years.

Last year, Cahill struck out 21% of the batters he faced and induced only 48.5% of his contact on the ground. Those were career extremes — high for the strikeouts and low for the ground balls — which is weird enough without looking at the whiff rates for his respective pitches, which look like a fork in an outlet. Then Cahill went out and changed his arm slot this spring.

The changes in his pitching mix might not be such a big deal. It looks like he stopped throwing his slider or cutter in favor of his curveball, which is fine. That change should have been a positive one. For his career, Cahill has gotten more whiffs (13.8% to 12.1%) and grounders (62% to 47.1%) from the curve, after all.

He’s still got the excellent change and sinker, and a breaking ball, which seems like it should be enough. For some reason, though, his sinker and change got fewer grounders last year than they ever had. This, despite him throwing it lower in the zone, on average. Check out where he threw the sinker to righties from 2011-2013 on the left, and where he threw them in 2014 on the right:

So it’s not location. The sinker did have an inch less sink on it last year than it ever had before, which is strange. It could be the reason he switched his mechanics this spring. He doesn’t quite come out and say it that way, but he does give some of the reasoning and demo his new mechanics here:

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Thanks to Jeff Wiser, we have spring video of the new delivery.

Here’s what it used to look like.

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We may need more regular season data and video to know what exactly will happen to his pitches from the new slot.

What we do know is that his new arm slot will mean new movement. It already has. Consistent with arm slot theory, the more over the top he goes, the more likely it is that he gets that sink back that’s been missing. He even mentioned it as part of the reason he made the change to Nick Piecoro.

So he might get his sink back, but how important is that for Cahill? In a quick, limited study, I checked the relationship between horizontal and vertical movement on the sinker and ground-ball rate, and vertical movement is indeed more important (-.59 r, p less than .0001 for vertical movement, minimum 100 balls in play, -.13 r, p=.15 for horizontal movement). Velocity may be more important that either movement, but this arm slot could help his spring velocity, too — he’s been up almost two ticks on the fastball this spring.

The movement numbers have not been as exciting, however, as the sink has not come yet. And a recent post by physicist Alan Nathan suggests that spin that goes along with the ball’s flight is useless spin — and going to a more over the top delivery may lose some of that perpendicular spin that is so useful. Cahill’s change is risky.

If Trevor Cahill has indeed found his sink, and more gas out of a new slot, it’s not impossible that he refinds his form. That’s worth the risk. If he pushes the ground-ball rate back to 60% and combines it with a big dropping curve and a good change, he could even combine different aspects of his past arsenal for better outcomes. It’s not impossible that he’s worth $13 million again next year after a return to form.

And that makes him a decent gamble, even at $6 million this year, for a team that’s rebuilding. After all, it’s just one year, and the alternatives were unexciting.