I know he wasn't going to use Britton. Probably didn't want to have Matusz start the inning, then not have him later. Ironic that after all the opportunities the Angels had they get the run on a bases loaded walk.
What was confusing to me was the intentional pass to a rookie who was just brought up (lefty Efren Navarro) to instead face righty Ianetta with two on, two outs.
I can only assume that he felt Hunter vs Ianetta was a better option than bringing in Matusz to face Navarro, which is dumbfounding given Ianetta's OBP - nearly .120 higher than his AVG. Only Trout has more walks on the team than Ianetta.
So what he ended up with was Matusz vs Calhoun, which, given Calhoun's numbers in the last 45 days, was easily the worst of all three scenarios.
In the end Buck blamed the strike zone (even tough FoxTrak showed all of the calls correct, and Buck wasn't exactly thanking the strike zone on Monday....) when it really came down to either you trust Matusz or you don't, and it was clear that Buck doesn't, and waiting two batters to bring him in with the bases loaded rather than earlier with first base open so he can maybe get the rookie to swing at some bad pitches was all on Buck.