"I have a great deal of respect for Ricky," Eustachy said. "He has worked very hard and has been extremely loyal to the people in our program. His time frame is my time frame."
Morgan averaged 2.6 points and 3.1 assists per game last season, while starting in 11 of the 29 contests he played.
His game seemed to blossom late in the season, as he started in ISU's final eight games and scored a career high 12 points at Oklahoma on Feb. 26.
The loss of Morgan leaves ISU with just one true point guard in the mix, first-year JUCO transfer Tim Barnes from Southeastern (Ill.).
Eustachy will need to get more minutes at the point from junior Jake Sullivan and true freshman Adam Haluska, a player he praised at last week's media day.
Eustachy also announced Monday that Iowa State center Chris Alexander has been suspended indefinitely from the Cyclone basketball program for a violation of team rules.
Alexander averaged 11.9 points, 8.1 rebounds and 2.3 blocks per game for Indian Hills last season. He was expected to bolster ISU's frontcourt this season, joining fellow transfer Jackson Vroman, Jared Homan, Adam Schaper and Andrew Skoglund.
He is the second ISU signee from the Ottumwa program to have problems. Jerome Harper was one of five signees in this season's recruiting class, but never made it to campus and has faced criminal charges stemming from a fight with a fellow student in Ottumwa.