"I didn't allow a lot of hard-hit balls out there, but I think I was trying to be too fine," Chen said through his interpreter. "I didn't have a big strike zone. So there comes a lot of walks. I kind of feel bad for my teammates out there, because my performance out there cost them."
Chen let a play he thought he should have made during a recent outing in Tampa Bay get in his head, and said he tried to not let that repeat itself on Monday.
"I tried not to think about it, but it's a big play," he said of the third-inning ball hit by Mookie Betts, which resulted in the first of Boston's four runs in the frame. "I didn't get the out that I should have. It affected me a little, but I tried not to let it bother me."
"He was all around the zone, a lot of close pitches, could have gone either way," catcher Ryan Lavarnway said. "It just didn't go our way."
While the line didn't hurt Chen's stats -- he allowed no earned runs -- the short start continued a troubling early trend.
"I just don't think that he's had the kind of consistent command like he will," manager Buck Showalter said. "I also think on the days when he's got a breaking ball -- something offspeed to make people think with that command -- he can make it look easy. But he just hasn't been consistent there. Usually, he bites back when he's had some things [go wrong]. He doesn't like not being good."
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Facebook and Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.