Johnson suffered a grade 2 MCL sprain and will miss four weeks, NFL Media Inside Ian Rapoport confirmed Monday. An MRI revealed no other damage in his knee.
Marvin Lewis told reporters after Sunday's practice that preliminary reports suggest Johnson "should be OK," according to NFL Media's Stacey Dales.
Dales reported that Johnson got up on his own will and was walking very gingerly before a cart came to take him off the field. The team did extensive testing on site as well.
The 28-year-old, who inked a four-year, $20 million contract this March, is part of a dominant right side next to Geno Atkins that will be crucial in order for Marvin Lewis' defense to generate a pass rush once again.
When last healthy together, the tandem helped Johnson to an 11 1/2 sack season back in 2012.