Ruf didn't start Tuesday while he awaits a medical opinion, but Mackanin doesn't believe it's anything serious. He said Ruf is available to pinch-hit, but he wasn't needed in the Phillies' 3-0 victory. Ruf is day to day.
Ruf and Howard's strong platoon splits give the Phillies hope for production at first base. Ruf posted a 1.107 OPS against left-handers last season, while Howard had similar success against righties, with an .802 mark.
Howard against left-handers is a different story, though, with just a .418 OPS in 100 at-bats against them in 2015. He entered the game hitless in three at-bats vs. Erlin.
Asche update: Mackanin said he expects outfielder Cody Asche to soon resume baseball activities.
"According to what I've read, he thinks he's turned the corner," Mackanin said.
Asche is flying to Philadelphia on Wednesday to be re-evaluated.
The 25-year-old outfielder missed most of Spring Training with a strained oblique. The Phillies placed him on the 15-day DL to start the season.
Asche's return should be highly anticipated by a Phillies team struggling to find offensive production from the corner-outfield spots. In six games before Tuesday, Tyler Goeddel, Cedric Hunter and Peter Bourjos have combined to go 6-for-47 (.128) with just 12 total bases.
Evan Webeck is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.