So, there was a blockbuster trade, where the Braves and Cardinals swapped one year of a talented but fragile left-handed right-fielder for a young Southern fireballing right-handed pitching prospect. If you started thinking that the Jason Heyward–Shelby Miller trade is slightly reminscent of the J.D. Drew/Adam Wainwright trade, you’re not wrong.

One main difference is that Drew was older and Wainwright was younger at the time of the trade than their present counterparts: Drew was 28 when traded and Heyward is 25, while Wainwright was 22 when traded and Miller is 24. Heyward has frankly been a much more effective player than Drew: in his five full seasons, he has averaged 136 games played and 4.9 rWAR, while Drew averaged 117 games played and 3.4 rWAR.

On the other hand, Wainwright had just spent the year in Double-A, whereas Miller has already thrown 370 innings with an ERA+ of 111. Wainwright, it must be said, was never quite the prospect that Miller was: before the 2004 season (around the time of the trade), Adam was Baseball America’s #49 prospect, and his top prospect ranking was as BA’s #18 prospect before 2003. Miller, meanwhile, was rated as BA’s #8 prospect before 2012, when he had his first cup of coffee, and as their #6 prospect before his 2013 rookie season, when he finished third in the Rookie of the Year voting.

On the other other hand, Heyward and Drew have slightly different skillsets. Drew played in a very different offensive context — the Steroid Era, to be blunt — but still, his pretrade triple slash was .282/.377/.498, a 124 OPS+, while Heyward’s is .262/.351/.429, a 114 OPS+. On the other hand, while Drew was a fine fielder, with 43 TotalZone fielding runs before the trade, Heyward was more than twice as good, with 98 fielding runs. (They were equally effective baserunners, each contributing nine runs on the bases.)

Generally speaking, hitting ages a lot more gracefully than fielding, because as hitters get older, they get slower but they also gain more power and draw more walks. (“Old player skills.”) Heyward still hasn’t put it all together as a hitter, and most of the value that he has contributed has been from skills that are not likely to age well; this is undoubtedly one of the reasons that the Braves were unwilling to pay what they believed would be the market price for Jason’s services. (Another is that, generally speaking, their owners are skinflints.)

Still, even if Jason Heyward isn’t exactly a sure thing, he’s a pretty known quantity, at least for a year: he’s one of the best players in the National League, even if you’re not sure whether the defensive numbers imply that he should be ranked in the top 10 or the top 30. He immediately makes the Cardinals better for a 2015 playoff push, and, you have to admit, he makes their team a little less hateable in the short term.

Shelby Miller is less of a known quantity, because he had a rough year last year. Tyrell Jenkins is almost a completely unknown quantity, a live arm in High-A with a big fastball who could wind up turning into anything from a workhorse starter to a power reliever to a washout, but his upside is significant enough that he’s worth watching. (Arodys Vizcaino, acquired in the La Stella trade, is two Tommy John surgeries past being considered as a starting pitcher, but he’s another live arm who could help in the pen.)

Anyway, here’s the thing with Miller: he was one of the top pitching prospects in the game before 2012, and then he had a really up-and-down year, pitching terribly in the first half. In late June, his ERA stood at 6.00, and his team tried to tinker with his mechanics and forbade him from shaking off his catcher. And, well, it worked: in the second half, he put up a “2.88 ERA in his last 10 starts, with a spectacular 70/7 K/BB in 59 innings.” He was so good in the second half that BA actually improved his prospect ranking from #8 to #6.

That reminds me of nothing so much as Julio Teheran, the #5 prospect in baseball coming into 2012, when Miller was #8. Julio also struggled in 2012. The Braves tweaked his delivery, too, and he didn’t even have as much of a second-half improvement as Miller. But then he went back to his original delivery, and you remember what happened: he was #5 in the Rookie of the Year voting last year (behind Miller at #3), and this year he was an All-Star.

So all I’m saying is that young pitchers can struggle and then they can figure it out. The Braves are buying low on Miller, and that’s appropriate — we wouldn’t have wanted to pay the price that it would have cost us a year ago. To say the least, it would have cost a lot more than a single year of Jason Heyward. But Miller has very good velocity, he has succeeded at every level including the majors, and the Braves pitching coaches have a track record of success.

That said, his struggles have been diagnosed, and they’re real. His swings-and-misses and his strikeouts are way down. He suffered from shoulder soreness in spring training in 2013, and after he pitched only one postseason inning in October, the team admitted that he was suffering from shoulder soreness in September, too.

That said, his 2014 ended a lot better than it started — from April-July, he had a 4.14 ERA, 81/55 K/BB in 121 2/3 IP, while in August and September, he had a 2.93 ERA with a 46/18 K/BB in 61 1/3 IP. With his fastball, you’d prefer to see something much closer to a strikeout per inning, but getting that K/BB back above 2.5 is absolutely crucial. Eno Sarris thought that part of his renewed success had to do with an increased reliance on high fastballs, and that’s certainly plausible. It’s also very possible that Miller is like Mike Minor, a pitcher whose shoulder soreness did not affect his stuff so much as it affected his command, but after half a season of struggling he finally managed to find his touch again. We’ll see.

There are generally three ways to get pitchers like Shelby Miller into your system: pay them $100 million on the free agent market, trade a boatload of prospects for them, or draft four pitchers like Shelby Miller and hope that one of them pans out. The Braves got themselves a Shelby Miller, and even if he’s not as shiny as he was when he rolled off the assembly line, I think that there are a fair number of reasons to be confident.

That doesn’t mean that this trade doesn’t existentially suck. The Braves didn’t cry poverty and trade Chipper Jones right before he turned into a free agent because they were owned by an eccentric billionaire who made all of his money in cable television and was the biggest private landowner in the United States, and who liked spending on baseball. Now they’re owned by a eccentric cable TV billionaire landowner who doesn’t like spending on baseball, so the team sold one of its best players for scrap. Still and all, the scrap they got back is pretty intriguing.