The San Diego Padres were in desperate need of a starter when Nick Pivetta landed on the injured list. Pivetta's departure couldn't have come at a worse time as veteran pitcher Griffin Canning and Joe Musgrove weren't ready to join the rotation from injury. And so, president of baseball operations A.J. Preller went to work. The Padres signed right-handed pitcher Lucas Giolito to a one-year, $3 million deal at the end of last month, but he has yet to make his season debut as he spent time in the minors ramping up. Giolito is set to make his first start for the Padres this weekend against the Seattle Mariners. The arrival of Giolito on the big league roster means the Padres will have to a clear a spot for the right-hander on the roster. Many speculated that meant struggling Matt Waldron's time was up . However, manager Craig Stammen revealed that the Padres aren't going to designate Waldron for assignment, and will instead move him to the bullpen as a length option.…