Colwill had already prompted questions earlier in the week when he remained on the bench for the 2-1 Premier League defeat by Arsenal, despite being fit enough to be involved. He returned to the starting line-up against Leeds but was replaced by Wesley Fofana in the 76th minute.
The defender then headed straight down the tunnel, leading to speculation that he had suffered another injury. However, his start against Leeds suggests the problem was limited, with Chelsea seemingly unwilling to take any unnecessary risks once the match had opened up.
Asked if the change was injury-related, Alonso said: "No, no. It is just from little things that he's having, but we don't expect that it's an injury."
Colwill has become an important figure in Chelsea's back line, meaning a further defensive issue would have complicated Alonso's selection options.
The Blues face Premier League fixtures against Hull City and Brentford before the international break, but can now temporarily put their concerns over Colwill's condition to one side.
