Heading into last year’s baseball draft, many expert observers had the Astros picking hard-throwing Stanford righthander Mark Appel with the first pick. Appel, however, fell all the way to the eighth pick and eventually spurned the Pittsburgh Pirates’ $3.8 million offer. As Appel learned last year, questions about signability can cause the presumed top prospect to tumble as clubs attempt to maximize their allotted budget. The 6-5, 215-pound Appel was 10-2 with a 2.56 ERA over 16 starts and 123 innings in 2012 at Stanford while earning consensus All-America honors as a junior. Appel was advised last year by agent Scott Boras, who is arguably the best at getting his [.]