If we're frustrated as fans, imagine how Gillespie feels as the player who lets his team and country down in more tests than not with injuries and stabbing pains in his ankles, knees, back, side, groin, shoulder, elbow, finger etc etc etc.
I feel sorry for the bloke, but I also feel sorry for Australian cricket because had he not been so injury-proned, he would have been a 300+ wicket bowler, perhaps one of the greats.
Bruce Reid had the same problem - meanwhile the rest of the bowling stocks find themselves either compensating for Gillespie's absence during the match, or being given temporary spots in the side while Gillespie is recovering, only to be dropped again on his return (i.e. Bichel).
If Gillespie makes it through the match then generally he is worth the effort - but only one innings from the big man with the mullet is going to continue to hurt the team.