Singer, a sophomore, had 66 catches with six touchdowns and averaged 16.7 yards per reception this past season. He will have two years of eligibility remaining.
Singer and Jacob Cowing (85 catches for 1,034 yards with seven touchdowns) were the first Wildcats teammates to surpass 1,000 yards receiving in the same season.
Monday was the first day for non-graduate transfers to enter the portal.
Arizona's leading tackler, safety Jaxen Turner, who had 79 stops, two forced fumbles, two fumble recoveries and two interceptions in 2022, also entered the transfer portal on Monday. So did defensive lineman Kyon Barrs, who had 39 tackles this past season.
The Wildcats finished 5-7 in 2022.