Haseley is among the most versatile players in the draft, having excelled as both an outfielder and pitcher for the Cavaliers over the past three seasons.
While there is a lot to like about the southpaw as a hurler, especially after going 9-3 with a 1.73 ERA and 0.96 WHIP in 2016, he projects as a position player professionally.
Haseley set career marks in nearly every offensive category in 2017, hitting .390/.491/.659 with 14 home runs in 58 games.
Here's what the internet thinks Haseley will bring to Philadelphia:
According to Michael Lananna of Baseball America, Haseley made some adjustments that have helped him develop into a far more potent hitter:
Perhaps the biggest difference in Haseley's game is the pop he has added at the plate after hitting a combined seven home runs in his first two seasons at Virginia.
As seen in this video courtesy of Virginia Baseball, Haseley is now a threat to leave the yard whenever he steps into the box:
Haseley has the makings of a potential five-tool player at the MLB level because of his hitting ability combined with good speed and impressive defensive skills in the field.
The Windermere, Florida, native has also played every outfield position during his stint with the Cavs, and that type of flexibility often comes in handy.
There were plenty of question marks surrounding Haseley entering the 2017 season, including what position he would play moving forward and whether he would prove to be deserving of a first-round selection.
He has answered those questions in emphatic fashion and is now among the Phillies' best and most dynamic prospects provided they are able to sign him.
This has been a disastrous season for the Phillies at the MLB level. They entered play on Monday with a league-worst 21-40 record, but the future still looks bright.
Haseley brings his tremendous offensive potential to a group of prospects that also includes star shortstop J.P. Crawford and last year's No. 1 overall pick Mickey Moniak.