LAKE FOREST, Ill. -- Chicago Bears wide receiver N'Keal Harry underwent surgery on his left ankle Thursday and will be sidelined for an unspecified amount of time, according to coach Matt Eberflus.

Harry sustained the injury on the first play of team drills Saturday when the ankle got wrapped up underneath linebacker Nicholas Morrow on a pass that went his direction. The 2019 New England Patriots first-rounder, who was traded to Chicago last month, could not bear weight on his ankle and was helped off the field by trainers and teammates.

Harry's injury is one of several at the wide receiver position for the Bears. Byron Pringle is out indefinitely with a quad injury, per the team, and rookie Velus Jones Jr. is classified as day-to-day despite missing the last week of training camp.

Chicago was without 21 players for the second day in a row at practice, its last before the preseason opener against the Kansas City Chiefs on Saturday. On the first day he was eligible to return to practice, linebacker Roquan Smith did not participate.

Smith, who demanded a trade in a statement earlier this week, was removed from the physically unable to perform list Wednesday. Smith passed a physical, according to the NFL transactions wire.

"He was cleared by our medical staff as healthy," Eberflus said. "He did not practice. And the reason why for that is, you'll have to ask him. We expect all of our healthy players to practice, and that was his decision. Like I said, you'll have to ask him. I have not talked to him about it."

The Bears did not make Smith available Thursday per the team's policy that only players who participate in practice are able to speak with the media.

Smith is officially a hold-in, akin to wide receivers DK Metcalf of the Seattle Seahawks and Deebo Samuel of the San Francisco 49ers, who were physically present at their team's respective facilities but did not practice before receiving contract extensions.

Eberflus said he did not have an "understanding one way or the other" whether Smith would continue to sideline himself from practice without a new deal.

Because he is present at training camp, the 2018 first-round pick is not subject to fines of $40,000 per day, which is the amount, according to the collective bargaining agreement, for players on their fifth-year option who have unexcused absences from training camp or are late to report without prior permission granted by the team.

It is unclear whether Chicago plans to fine Smith for skipping practice.

"That discipline really comes from the front office," Eberflus said. "... I'm not going to get into the details of what discipline is there. But we will certainly work through that when the time comes."

Asked to clarify whether Smith's absences will be unexcused if he continues to skip practice while deemed healthy, Eberflus said, "We'll work through that when we get there."