During the Angels' series against the Tigers earlier this week, Middleton recorded the first two holds of his nascent career, marks that reflect his development as a reliever.
"This is the best we've seen him throw," Angels manager Mike Scioscia said. "This was the way he was throwing towards the latter part of last year, when he jumped on everyone's radar."
Middleton, a third-round Draft pick of the Halos in 2013, shifted to the bullpen last year after struggling to find success as a starter in the Minors. After transitioning to relief, Middleton's velocity ticked up and hit triple digits, helping trigger his rapid ascension through the Angels' farm system. He climbed three Minor League levels in 2016 and earned an invitation to Major League camp this spring, though he logged a 7.71 ERA in seven Cactus League appearances and opened the season in Triple-A.
"Out of Spring Training, he was searching for some things," Scioscia said. "He came up here and made some adjustments when it still looked like he was searching for things. Then you saw the stuff appear. You saw the power slider, the explosive fastball. There's no doubt that he's made improvements. He's much better than he was in Spring Training. If he can pitch along the lines of where he did towards the latter part of last year, he will be a guy that we'll move toward the latter parts of our game."
• Center fielder Cameron Maybin, who logged four steals and four runs in the Angels' 9-4 win over the Astros after coming off the disabled list on Friday, was out of the lineup on Saturday. Scioscia said the Angels wanted to give Maybin a chance to bounce back after his busy day on the basepaths.
"As hard as he played last night, it'll be a good recovery day for him," Scioscia said. "We'll get him back in there tomorrow and we'll hopefully start to get him in there on a regular basis."
Maria Guardado covers the Angels for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.