We all knew that there was a fairly high probability that Derek Holland would not be back with the San Francisco Giants next season, especially with Farhan Zaidi being hired to come in and shake things up.
After a solid 2018 in which he won seven games and recorded a respectable ERA of 3.57, his value as a bottom of the rotation starter skyrocketed. The Giants most likely feel that they would be better served going with a cheaper option in 2019 like Chris Stratton.
I agree with this mode of thinking. With the Giants unlikely to compete in 2019, it doesn’t make sense for them to give too much money to an average starter who won’t put them over the playoff threshold.