Veteran right-handed pitcher Lucas Giolito needs to be added to the San Diego Padres roster by this Saturday, which will force the team into a tough roster decision. San Diego will need to replace someone in the starting rotation with Giolito, but who that will be remains to be seen. The expected options are right-handers Walker Buehler or Matt Waldron, both of whom have been up and down this year. San Diego could always go with a six-man rotation after bringing Giolito up, or even move guys around to keep someone in the bullpen. Giolito has made four minor league starts as he works his way back to the big leagues. So far, the right-hander has posted an ERA of 4.76 over 17 innings of work. San Diego has multiple options to choose from, but it won't be easy since both Buehler and Waldron have been strong as of late. But having more arms to work with could be good for the Padres to consider, especially with all the injuries and uncertainty that the starting group has seen this season.…