School officials said in a statement that Theodore Hammonds collapsed after a non-contact drill Tuesday and was tended to by the team's staff.
Polk County Emergency Services took Hammonds to a hospital where he died.
School officials said they don't know what caused Hammonds to collapse and that their thoughts and prayers are with his family and friends.
The Ledger reports Hammonds had caught 14 passes for 193 yards and had two touchdowns in four games.
Hammonds is from Miami.
Warner is scheduled to play Keiser University on Saturday in Lakeland.
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