Some strange changes--follow-up to power fight at work

A couple of months ago, I told a story about my boss and a sr director fighting for leadership role for one of my programs. Eventually things settled. My boss won the power fight in that round. Sr. director took medical leave starting last week. The timing is very strange. It is right at the moment that this group seems to need him most (in my opinion, no one really needs him, but some would argue..).

anyhow, I have talked with my boss and big boss about my interests in that area without knowing that sr. director would take the leave. Should I step up at this critical moment to work in his replacement, not taking the lead but gain myself some work expereince in this role so that I can put it in my CV for future? It is tricky since I don't have any former expereinces but I know I can do the work. Frankly, I believe they all know I can do the work, just need an opportunity to show it.