The thing that sucks about the combination of Brujan's IL stint and Workman's slow start (in very limited at bats) is it probably means Workman doesn't get any time to adjust to MLB and the Cubs will replace him with Brujan as soon as he is ready. If Brujan hadn't got hurt and had been DFA'd, Workman would have had a little more rope.
Jed is too busy looking for the next post-prime closer to sign or trade for, hoping for him to reclaim his glory days while saving Tom a few hundred bucks.
It sucks in that situation because Happ probably doesn't swing at the 4th pitch if the count was 3-0. So essentially, that one bad call changed the outcome of the entire at bat.
As well as the Cubs have been playing, the young players who we were hoping to see step forward really haven't done anything... PCA, Shaw, Busch, even Workman (in limited at bats).
Or, I don't know, maybe Jed has been here long enough that he can take responsibility for not being able to develop reliable bullpen arms from within the organization.
The answer is probably trading away prospects at the deadline for short term bullpen help, rather than just having spent money for it in the off-season.
Jed prefers to give a bad pitcher $5M rather than spend $8-10M on a good pitcher. That's money right in his boss' pocket, and his performance incentives are all tied to cost savings.