Sanchez has 18 months left on his contract at Arsenal.
The last meeting between the two sides in the FA Cup was in 1999 when Arsenal won 4-2.
Osimhen was the African Youth Player of the Year in 2015.
Sanchez and Mesut Ozil's current deals with Arsenal expire at the end of next summer.
Arsenal manager Arsene Wenger's contract at the Emirates will expire at the end of the 2016/17 season.
Arsenal boss also discussed the futures of Carl Jenkinson and Mathieu Debuchy during latest press conference.
Spanish midfielder is not progressing as quickly as hoped in his recovery from ankle surgery.
Gunners boss reveals latest on Lucas Perez, Mesut Ozil, Francis Coquelin, Danny Welbeck and Theo Walcott.
Alexis and Ozil have 18 months left on their current contracts.
Cohen Bramall plays for seventh-tier club Hednesford Town FC.
Coquelin went off with a suspected hamstring injury after just 26 minutes.
Chelsea have made contact with Rodriguez's agent to sound out Wolfsburg defender's availability.
Gunners boss confirms Mesut Ozil will miss third game in a row at Preston North End in the FA Cup.
Jack Wilshere has 18 months left on his contract.
Contract negotiations involving Alexis Sanchez and Mesut Ozil will continue to dominate Gunners' agenda.
Debate has already begun after Arsenal striker's stunning effort in Sunday's 2-0 win over Crystal Palace.
Oxlade-Chamberlain has 18 months left on his current deal.
The 31-year-old wants to leave the club during the January transfer window.
Welbeck suffered a knee injury in May during a game against Manchester City.
Reus' contract at Borussia Dortmund will run down in 2019.
Theo Walcott has scored 11 goals this season, second only to Alexis Sanchez.
Arsenal are currently nine points behind leaders Chelsea.