On 14 January 2007 Kalac suffered an injury against Reggina and was replaced by a recovering Dida for the following match against Lazio. These goalkeeper injury concerns prompted manager Carlo Ancelotti to sign Messina goalkeeper Marco Storari, who became the third goalkeeper in the Milan first team with veteran Valerio Fiori being the fourth. Storari replaced Dida and Kalac in Milan's Serie A matches against Livorno and A.C. Siena in mid-February, when both were out with injuries. Despite this extra competition, Kalac recovered from injury in time to play for Milan in the first leg of the UEFA Champions League round of 16 against Celtic on 20 February. In the next Serie A match against Sampdoria five days later, Dida was nevertheless able to make his comeback after being out for nearly one month and subsequently remained in goal until suffering a shoulder injury in mid-April, which enabled Kalac to make further two Serie A appearances before Dida returned in goal for the first leg of the UEFA Champions League semifinals against Manchester United on 24 April. Kalac finished his second season at Milan having made 10 appearances in the Serie A and another 3 in the Champions League.