MLB draft expert Eric Longenhagen will provide pick-by-pick analysis of the opening two rounds (and both supplemental rounds) of the 2015 MLB draft.

Before diving into the analysis, here are some notes and helpful links related to the draft:

• Feel free to follow along, using our draft tracker and Keith Law's latest mock draft.

• All players' names link out to more in-depth scouting reports of that guy, written by Christopher Crawford, Keith Law and myself.

• We will include the compensation round (10 picks) and competitive balance A round (six picks) at the end of this analysis.

• We use the 20-80 grading scale for all MLB prospects.

1. Arizona selects: Dansby Swanson, SS
Vanderbilt
Rank in Keith Law's Top 100: 3

Finally, we have an answer. After a spring of aggressive scouting by Diamondbacks general manager Dave Stewart and incessant discussion about potential money-saving moves, the Diamondbacks select Swanson with the first overall pick. Swanson represents the best combination of positional certainty and offensive impact among the shortstops at the top of the draft. He's going to get on base, swipe some bags and hit for power while playing solid defense at shortstop despite an average arm. He should move quickly, though don't be surprised if he swings and misses a bit. Teams near the top of the board all love Swanson, and his camp will likely use that leverage to coax a sizable bonus out of Arizona. The Snakes might save some money here, but don't expect it to be enough for them to select another huge name with their next pick. Law scouting video