The winger sustained some form of foot injury and had to be helped off before the end of today's training session. While club sources expressed optimism to Corriere dello Sport that Callejon won't be gone for long, it's very unlikely that he'll play against Inter this weekend.
Fortunately Dries Mertens will be available after sitting out the Udinese match suspended for yellow card accumulation. The Belgian winger hasn't quite been in his top form of late, but his brand of wide play with clever movement and incisive passes should be of great use with the way Walter Mazzarri sets up his defense.
Callejon will be joined on the sidelines by Federico Fernandez, who was sent off against Udinese after earning two yellow cards. How that shuffles the lineup for Rafa Benitez remains to be seen; Miguel Britos was out injured against Udinese, and his status for the weekend remains unclear.
Henrique Buss could be moved inside after spending most of his time at right back recently, but who would step in at right back could be up for debate. Anthony Reveillere has been... well, he's been really bad for the last several months. Giandomenico Mesto has been healthy for a month after a serious knee injury earlier in the season, but has played a whopping eight minutes of football since then. Camilo Zuniga is finally healthy, but may not have the fitness levels needed to start yet.
It looks like it's going to be a challenge for Rafa and company this weekend. Hopefully Callejon is only out for the one match, because Napoli have enough issues to worry about without dealing with problems up front as well.