"I was able to return to work last night after receiving great medical care," Lewis said in a statement on Wednesday. "I especially want to thank all of the doctors, nurses and technicians who treated me. I am glad to be back with the team as we prepare to play the Buccaneers on Friday."
Speaking to reporters Wednesday, Lewis said doctors originally thought he was dealing with something more serious than a cyst and "was glad" it wasn't a major issue.
"I went to practice yesterday. I didn't really miss, I just left early," Lewis said. "They wanted me to go back and have another couple tests done. I had three tests done yesterday. They asked that I go and get it done. My point was that two hours wasn't going to make a huge difference. Then I was back here by five."
Lewis missed part of Tuesday's practice with what the team termed a "minor" health issue.
NFL Network's Stacey Dales reported Tuesday that Lewis was dealing with a cyst in his knee. A Baker's Cyst is a fluid-filled cyst in the knee that can cause joint swelling, according to the Mayo Clinic.
The 58-year-old coach enters his 15th season leading the Bengals. During the stint, Lewis has compiled a 118-103-3 record with seven playoff appearances, but no postseason wins. Cincinnati was 72-152 (.321) in the 14 seasons prior to Lewis (1989-2002).
Lewis' quick return is a positive sign heading into the regular season, but it's a situation that could require monitoring as we move deeper into 2017.