MLB Draft Tracker: Astros take Mark Appel No. 1

The 2013 MLB draft begins Thursday night at MLB Network studios in Secaucus, N.J. Dave Perkin, a former major league scout and Baseball America contributor and SI.com's draft expert, will have analysis of each first round pick. To check out Dave's third and final Mock Draft for 2013, click here.

NOTES: There are 33 picks because of various compensation rules. The Pirates failed to sign Stanford righty Mark Appel after drafting him last year and are thus given a pick one slot below where he was taken in 2012.

Under a new system this year tied to compensation for lost free agents, teams would gain a first-round draft pick if a player to whom they had made a qualifying contract offer rejected that offer. The Yankees therefore received two picks at the end of the first round as compensation for losing Rafael Soriano (to the Nationals) and Nick Swisher (to the Indians) in free-agency.

Three teams -- the Nationals (for signing Soriano), the Brewers (for signing Kyle Lohse) and the Angels (for signing Josh Hamilton) do not have first round selections because they signed players who had turned down qualifying offers from their old teams. The Cardinals, Rangers and Rays gain additional picks for losing Lohse, Hamilton and B.J. Upton, respectively. The Braves lost their pick for singing Upton but added it back when Michael Bourn signed with the Indians. For a more detailed breakdown of the rules behind this new system, click here.