Coach Steve Spagnuolo said Monday doctors would give Amendola an extra day before administering tests Wednesday.
Amendola has played in five games since the Rams signed him off the Eagles' practice squad Sept. 22. He's averaging 24 yards on kickoff returns, 8.5 yards on 11 punt returns and has 15 receptions with an 8.5-yard average.
The Rams also said guard Jacob Bell will undergo concussion tests on Tuesday.
St. Louis (1-7) has a bye this Sunday.