Shawn Springs and LaRon Landry were not in attendance at Monday's OTA practice.
"They had the opportunity to be here and chose not to [attend]," head coach Jim Zorn said.
Santana Moss was excused from Monday's OTA due to the flu.
The OTAs are voluntary for players to attend, although Zorn jokingly likes to say they are "voluntary mandatory."
Zorn said he planned to telephone both Springs and Landry to get a read on their plans.
"I want to get a feel for why they decided not to come," Zorn said. "I also know that we have great participation here. [Springs and Landry] did participate in the first eight practices [in early May]. It is not something that I am going to make a huge spectacle of. We will just see what happens.
"I don't want to really comment because if I said I was really disappointed, and they had a legitimate reason for not coming, then I would mis-speak. So I'm going to try not to do that."
Springs, an 11-year veteran, did not attend any OTA sessions last year. Landry is in second season in the NFL.
Defensive coordinator Greg Blache had the quote of the day regarding Springs and Landry.
"I have to worry about the guys who are here," Blache said. "It's like you guys in the media--you're probably worrying about the girlfriends that left you instead of worrying about the people that love you.
"You take care of the people that love you. You don't worry about the ones that left."