Aiken (elbow) is currently pitching in extended spring training, and sat at 89-92 mph in his first start there in late May, Fangraphs' Eric Longenhagen reports.
He underwent Tommy John surgery in late May of 2015, so this is his first live action against hitters, so it's not a huge red flag that his velocity is not all the way back to his pre-surgery days. Longenhagen reports that Aiken's curveball retained impressive shape and his changeup was below average, which is to be expected given where Aiken is at in his development and recovery. Aiken has also added some weight, and is now approximately 230 pounds, despite being listed at 205. He should spend most of the year in Arizona at extended spring training and rookie ball, although it's possible he could head to Low-A later in the season. Dynasty league owners who drafted Aiken knew the risks and the distant ETA involved, so it's just nice to know that he's back competing on the mound.