Say what you like about the effectiveness of Seranthony Dominguez's fastball relative to last season. The Phillies believe that his best path back to being a dominant reliever is the fast lane.

Dominguez has struggled so far this season, and lately in particular, giving up runs in four of his last eight appearances. He entered a one-run game in the seventh inning Thursday against the Brewers and gave up a three-run homer to Yasmani Grandal that all but put the game out of reach.

Grandal’s homer came on a changeup, Dominguez’s third-best pitch. But it’s his blazing fastball that has been getting hit. After holding opponents to a .203 average and .305 slugging percentage with his heater last season, Dominguez has allowed a .289 average and .447 slugging on that pitch this year.

"Watching his fastball [Thursday], it was as good as it's been in a long time. I think [Thursday] was pitch selection," manager Gabe Kapler said. "I think he could've made a better choice to stay with that fastball given how effective and electric it was."

Indeed, it's possible that Dominguez has lost some confidence in his fastball. Kapler conceded that Dominguez's velocity dipped slightly in spring training. It has normalized recently, averaging 97.3 mph according to Statcast. Last year, Dominguez's average fastball velocity was 98 mph.

"I think it's beginning to come back to its normal levels, its normal life," Kapler said. "I think that we're going to see some poor contact going forward with Seranthony."

Extra Bases

Scott Kingery continued his injury rehab assignment at double-A Reading. He was scheduled to play half the game at third base and the other half in center field, part of the Phillies’ plan to give him time at multiple positions before reinstating him from the injured list. “Once we feel like we’ve adequately checked those boxes, we’ll bring him back,” Kapler said. ... Reliever Victor Arano (right elbow inflammation) threw an all-fastballs bullpen session. Next up: Incorporating offspeed pitches before going on an injury rehab assignment. ... For the second consecutive series, a team called up its top prospect against the Phillies. Rockies second baseman Brendan Rodgers made his big-league debut at Citizens Bank Park on Friday night, three days after Brewers second baseman Keston Hiura did the same. ... At a press event Friday at City Hall, Mayor Jim Kenney and Gov. Tom Wolf threw their support behind a campaign to get former Phillies slugger Dick Allen elected to the Hall of Fame in 2020. Allen’s son, Richard Jr., was in attendance. ... Aaron Nola (3-0, 4.86 ERA) will be opposed Saturday by Rockies right-hander Antonio Senzatela (3-2, 5.35).