The Cleveland Indians announced the signing of 1st round pick Brady Aiken in a tweet just a few minutes ago. His signing bonus has not yet been announced. (The team was well below slot on its overall budget going into today.)
Aiken was the #1 overall pick in 2014, but after a physical led to concerns about his left elbow, he and the Astros were unable to agree to terms. Houston's immediate move upon hearing back about his medical tests was to slash their offer down the very minimum they could offer while still receiving a compensation pick. They later upped their offer a bit, but it seems Aiken had made up his mind by then that he didn't want to sign with them.
Their concerns were not completely unfounded, as Aiken underwent Tommy John surgery in March. Still, he was viewed as the most talented high school pitcher in years, and the success rate for pitchers returning from the operation is good.
Aiken has a great velocity on his fastball and has multiple other plus pitches. He won't be pitching in any sort of game during the rest of 2015, but is expected to be ready by spring training. The Indians will likely limit his workload in 2016, but he has the kind of stuff that could allow him to move quickly through the system, and a debut as early as 2018 is certainly not out of the question.