He should be a serviceable #4 starter with 10-12 wins, about 120-135 K's, ERA around 3.8-4.00. The issue with Lowry is whether he can adjust to the batters after they face him multiple times. In the minors, he struck out close to 1 batter an inning. That ratio has started to slip, but he is a lefty and he will be pitching in rival Petco and Dodger Stadium enough times to keep his stats steady.
I have him on my team and I think his poise and the strong offense behind him will make him a sleeper. He may even outperform Jerome Williams, who is not a strikeout pitcher.