the club and Mourinho value long serving players for the captain's role. the longest serving player around the first team (assuming courtois replaces cech) will be Ivanovic, he is a bit temperamental. I remember the game against West Brom last season. after Ivanovic it's Cahill, so I'll say Cahill for the short term when JT leaves. but it's weird to think Cahill is one of the longest serving players at the club. he's only been here 2 years