Fischer was 1-0 with three saves and a 3.65 ERA in nine relief appearances with eight walks and 28 strikeouts over 24⅓ innings for the Suns.
At Auburn last summer, he was 3-3 with a 4.96/4.30/1.43 pitching line in eight starts and four relief appearances after being drafted in the 18th round out of UConn.
A corresponding move for Potomac has not yet been announced.
UPDATE: To make room on the Potomac roster, RHP Tyler Herron has been promoted.
Herron was signed this past offseason as a reclamation project, having pitched 2012 with the Fargo-Moorhead Redhawks of the independent American Association. A former first-rounder with St. Louis in 2005, off-the-field issues forced Herron out of affiliated ball by 2009. He spent 2010 with the Kalamazoo Kings of the Frontier League, but missed the 2011 season with an arm injury.
This season, at the age of 26, Herron was 1-1 with one save and a 1.77 ERA in ten relief appearances with 11 walks and 32 strikeouts over 20⅓ innings for Potomac.
With an off day today, a corresponding move for Harrisburg will most likely be announced on Friday.