"I tried to go. We didn't make a decision til early in shootaround," Deng said after the game. "Last game [against Miami] I wasn't sure for the game. I was able [to play], I felt better throughout the day. I tweaked it a little bit in the second quarter last game and it just kind of flared up on me the next day. A lot of swelling and I've still got a lot of swelling in it."
Deng said he received an MRI but the results came back clean.
"Mostly I just got to ice it as much as I can, elevate it, just try to get the swelling down," Deng said. "But [we had] an MRI and everything was fine."
Deng said he has never had an Achilles injury before and that he is hopeful he can be back when the Bulls start a stretch of four games in five nights on Tuesday.
"I want to get back as soon as I can," Deng said. "We're going to treat it these next two days. My mindset is to be ready for the next game. If I feel like I can run out there I'll play. I don't know about the minutes, I don't know how much I'll play, but where it's good enough and comfortable enough to be effective out there."
Bulls coach Tom Thibodeau, who said before the game he thought Deng's injury was in his left calf, said Deng would remain day to day and isn't sure how long this latest injury will linger.
"I don't know other than what [athletic trainer] Fred [Tedeschi] tells me. He was unsure this morning, he had tightness, they wanted to work on him and he just said it could be better in a couple days," Thibodeau said.
The Bulls miss Deng's scoring punch in Saturday's 92-75 loss. He is averaging 19.4 points a game and has scored at least 20 in his past six contests.
"He's been playing great," Thibodeau said. "Actually he said he thinks he did it in the previous Detroit game [on Nov. 27]. He's just had the tightness, and it hasn't gone away. He had some swelling, so he's trying to get that down."
The news of the injury came as a surprise given Thibodeau didn't address it in his first remarks to reporters after Saturday's shootaround. Bulls center Joakim Noah revealed news of Deng's injury in response to a question about the ups and down the Bulls have already endured this season.
"I don't know if Lu's playing tonight," Noah said midway through his answer. "He's got to get his Achilles right. But whatever it takes we got to find a way. We're playing against a very good team who's playing very well right now. And we just got to find a way to win at home."
Thibodeau eventually came back out to address Deng's injury with reporters.
The good news for the Bulls is that Thibodeau sounded more optimistic regarding Butler's health than he has in recent days. Butler has been out since injuring his toe on Nov. 18 against the Charlotte Bobcats.
"Jimmy's doing more and more each day, so he's getting closer," Thibodeau said. "Mike [James] is on the bike now, so that's a good sign.
"He's moving a lot better, so he's actually pretty close. But I want to see a practice with some contact in it before he gets out into a game. But he's moving now pretty much as close to a game speed as you can get."