Alexander was brought in for a workout with the Giants on Monday, Aaron Wilson of ProFootballNetwork.com reports.
The Raiders waived Alexander on Tuesday with a non-football injury designation.
Alexander was placed on the did not report list Friday, Scott Bair of NBC Sports Bay Area reports.
Alexander (concussion) is inactive for Sunday's game against the Chargers.
Alexander sustained a concussion and has been ruled out for the remainder of Monday's game against the Eagles.
Alexander (ankle) is inactive for Sunday's Week 9 game against Denver.
Alexander (ankle) is active for Sunday's game against the Buccaneers.
Alexander (ankle) is inactive Sunday against the Jaguars.
Alexander (ankle) will not play against the Chiefs on Sunday, CSN's Scott Bair reports.