ESPN More Sports

In the span of two days, the Florida Marlins parted ways with the two primary pieces they received in the 2007 trade for Miguel Cabrera.

Andrew Miller and Cameron Maybin were considered elite prospects at the time of the trade, but neither developed into legitimate contributors.

Miller has failed to blossom since being selected with the sixth pick in the 2006 MLB Draft -- ahead of pitchers Clayton Kershaw (seventh) and Tim Lincecum (10th). On Friday, he was traded to the Boston Red Sox for minor league reliever Dustin Richardson.

On Saturday, Maybin was dealt to the San Diego Padres, for pitchers Ryan Webb and Edward Mujica. Both will help with the Marlins stated desire to improve the bullpen, but this is a disappointing end to Maybin’s tenure in South Florida. The Detroit Tigers drafted Maybin in 2005, ahead of notable outfielders Andrew McCutchen, Jay Bruce, Jacoby Ellsbury and Colby Rasmus.

With Miller and Maybin gone, two questions remain: How did the Cabrera trade end up working for the Marlins, and, what can the Red Sox and Padres expect out of their acquisitions?

According to Fangraphs.com’s Wins Above Replacement, the Marlins experienced a “loss” of 8.5 WAR on this trade. Cabrera has accounted for all of the positive contributions among the players the Marlins traded, but he’s been an MVP-caliber player during his tenure with the Tigers.

So what can be expected from Miller and Maybin? Neither player has produced at the Major League level, with Miller’s erratic command and Maybin’s strikeout issues and contact ability. Miller has faltered, even after return trips to the minors. Maybin has shown the ability to dominate at the minor-league level, but has seen his holes exploited in the big leagues.

Maybin did not accumulate enough plate appearances to qualify, but if he had his swing-and-miss percentage at balls inside the strike zone (82.1 pct) would have ranked 11th worst in the majors last season. A majority of the players with worse marks in that category are power hitters like Ryan Howard, Adam Dunn and Mark Reynolds.

Maybin’s issues with making contact is what holds him back from developing into the star many people projected him to be. He has a career .306/.393/.478 line in 1,793 career minor-league plate appearances, including a .340/.415/.525 mark in 2010. He struck out in just 18.5 percent of his minor-league plate appearances last season.

Maybin will be just 24 years old next April, giving him plenty of time to carve out a productive career. But the difference between him being a Quadruple-A specimen and a legitimate Major Leaguer will likely come down to his ability to reduce his strikeouts and improve his contact rate with his new club.

It has been a rough spring for a lot of pitchers, and while you can usually ignore spring training results, three guys in particular are pitching in a way that should worry you: Rich Harden (8 1/3 IP, 7 BB, 9 K, 2 HR), Madison Bumgarner (7 IP, 7 BB, 0 K, 1 HR) and Andrew Miller (7 2/3 IP, 8 BB, 2 K, 1 HR). But the most telling number can't even be found in their stat lines.

Harden is coming off another injury-riddled season, so spring training represents an especially important tune-up, while Bumgarner and Miller are young guys looking to get spots in the big league rotation. Each of these guys have some real incentives to bring their best stuff even in games that don't count. Walking seven guys while striking out none in seven innings as Bumganer has is very troubling, even if it is just seven innings. But even more telling is fastball velocity.

Over seven innings a pitcher throws about 60 fastballs, and a given pitcher's fastball speed does not vary by much, so 60 fastballs gives a pretty good picture of a pitcher's true talent. And fastball speed is tremendously important. The average fastball that is swung at is missed 14 percent of the time, and on average each additional 1.25 mph increases this rate by 1 percent. More swinging strikes mean less contact and more strikeouts. Not surprisingly, there is a clear trend showing that pitchers who throw faster perform better.

This is especially troubling for Harden and Bumgarner, whose fastballs have been noticeably slower during spring training. Last Monday the two pitchers actually faced off in the Ranger's spring training park in Surprise, AZ, one of the few springing training parks with the Pitchf/x system.

Harden's fastball was sitting in the 88 to 91 mph range topping out at 92.1 mph. His average speed last year was over 92 mph. Bumgarner worked in the 88 to 90 mph range, topping out at just 91 mph. He was regularity above 90 mph last year in the minors, and his fastball is his best pitch. However, his velocity did start to fade towards the end of last season, which makes his lack of velo this spring even more concerning. Some pitchers can succeed with a slower fastball, but the reduced speed coupled with the very poor performance is not encouraging.

Miller is a cautionary tale for Bumgarner about what can happen when a pitcher's velocity goes away. Once an elite prospect who could regularly throw 95, his average fastball just 90.9 MPH a year ago, and his stock has tumbled significantly. A disastrous spring certainly won't help get him back in the Marlins plans.

It's always possible these guys are still a step behind after a long winter, and that their velocity will return. But when trying to figure out which spring training stat is most telling for pitchers, start with fastball velocity.

Dave Allen is an author of FanGraphs.