I wouldn't have mind signing Murphy to platoon at third with Garcia while giving Garcia other AB's in left when they figure out that Olivera is a bust.
Speaking of Garcia, despite what Bowman and co. report his range numbers at third were good so he's not anywhere near CJ bad defensively there. He will make some bad errors from time to time however. He only had a -3 DRS with us there last year and was actually very good in LF showing good range and saving a run. So he seems quite good defensively in LF. See here: http://www.fangraphs.com/statss.aspx?playerid=13777&position=3B