For the vast majority of baseball fans, deadline deals in which contending teams push for the playoffs are mysterious in nature. Far more fans only see the big name coming to save the day as a good thing, rather than lament the loss of obscure minor leaguers whose name they’ve only just learned. The trend is changing as the internet opens up the vast minor league universe to hardcore fans but, for the majority of baseball fans, the names of prospects have very little in the way of context attached.

This week represents a turning point for two fanbases, as “the guy we got for Haren” and “the guy we got for Anibal” will make their respective débuts this week. Jacob Turner — key piece going from the Tigers to the Marlins in the Anibal Sanchez/Omar Infante deal — and Tyler Skaggs — the main prospect haul from the Dan Haren-to-the-Angels trade of 2010 — are probable starters on Wednesday at Chase Field. As fate would have it, they will take the mound in either end of tomorrow’s unusual voluntary doubleheader in Arizona.

Jacob Turner is not making his big league debut, as that came in 2011 at the tender age of 20 while still a member of the Detroit Tigers. Fishstripes has a great breakdown of what Marlins fans can expect from Turner during those excruciating minutes between Giancarlo Stanton at bats.

Turner’s three start cameos with the Tigers in each of 2011 and 2012 were not exactly thrill-a-moment rides, as the 21-year old righty walked seven against seven strikeouts in 12 and a third innings in his most recent big league stint. As (former podcast guest!) Michael Jong points out, Turner has been a bit of mess in 2012 despite posting decent ERA numbers in the minor leagues. The Marlins hope Turner can be the mid-rotation start who, with improved command, can capitalize on his strong ground ball rates and swing-and-miss stuff to provide plenty of innings at the big league level.

In Tyler Skaggs, the Diamondbacks have a pitcher on the other end of the spectrum, in a way. Skaggs is a lefty with sparkling numbers at all minor league levels. Some concern occasionally surfaces that his minor league success is a virtue of simply being left-handed with a curve he can throw for strikes. Many pitchers have breezed through the minor leagues only to realize that big league hitters don’t scare quite as easily.

Skaggs added a change up as a pro that continues to draws raves, from Keith Law (preseason) to Jason Parks (at the Futures Game). Skaggs is the Diamondbacks number two prospect behind Trevor Bauer. At least he was, anyway.

Good prospect watchers like Goldstein, Law, and Parks, are well-conditioned to look for both the upside and possible pitfalls. But even the slightest misstep at the highest level shows the frailty of prospect prognostication – it hints at the high bust rate that nobody wants to consider when road mapping an endless cycle of success for their chosen club.

Both Trevor Bauer and Jacob Turner made a handful of ugly starts in the big leagues this year and, as a result, their relative stocks ceased to rise. In relative terms, Tyler Skaggs remains unspoiled by the realities of life in the Major Leagues. He is yet to be touched up by Giancarlo Stanton or, more realistically, taken deep by a jobber like John Buck. John Buck might be a below-average big leaguer at this point but he still represents a significant upgrade in talent over 99.99% of hitters Tyler Skaggs faced in the minor leagues.

Whether Turner can ever reach the number 2 starter potential some saw for him remains in doubt, just as it remains in doubt that Skaggs ever becomes that type of player. Long is the way, and hard, that out of minor league drudgery leads up to riches. One start, head-to-head, won’t tell the entire story of either player’s big league career.