The designation does not mean that Fitzgerald or Sherfield tested positive for the virus because the list is also used for players who have come into close contact with someone who has returned a positive test.
Fitzgerald would have entered Sunday's game coming off of one of his strongest outings of the season, after adding 62 yards on eight receptions against the Seattle Seahawks—tying his season high in both categories, which was set when he caught all eight targets for 62 yards against Seattle in Week 7.
Though he has yet to find the end zone this season, Fitzgerald is a major piece of the Cardinals' offense. He falls in behind DeAndre Hopkins on the Arizona leaderboards with 43 receptions, good for a total of 336 yards.
Even with Fitzgerald sidelined, the Cardinals will still have some of their most powerful pieces come Sunday. Hopkins has reeled in 72 catches for a league-leading 912 yards and four scores for the 6-4 Cardinals this season. Wideout Christian Kirk ranks second on the team in receiving yardage, with 477 yards on 31 receptions. And that's just looking at their passing game.
The Cardinals offense, which paces the NFL in yards per game (414.3, just barely leading the Kansas City Chiefs at 414.1), largely relies on its rush, with 157.7 yards per game coming on the ground, ranking second league-wide. Most of that production comes from running back Kenyan Drake (641 yards) and quarterback Kyler Murray (619 yards).
Before Fitzgerald missed time at the end of the 2014 season, he had appeared in every regular-season game for the Cardinals since 2008. The 37-year-old, who earned 10 of his 11 Pro Bowl nods from 2007-17, signed a one-year deal worth $11 million ahead of this season, his 17th in the NFL.