Even so, Mackanin wouldn't rule out starting Ruf in left field as soon as Sunday.
"In the next few days, if I don't see improvement," he said. "I'm going to be forced to do it."
Cedric Hunter and Peter Bourjos, the starting corner outfielders, were a combined 3-for-23 as the Phillies lost their first four games. The Phillies scored just two runs in three of the four losses.
"At some point, you've got to infuse some offense in there," Mackanin said. "I don't want to take Bourjos or Hunter out of the lineup, but they're not hitting."
Ruf's main role coming out of Spring Training was as part of a platoon with Ryan Howard at first base, with Ruf starting against left-handed pitchers. But the Phillies faced only one left-hander in the first four games of the season, and they aren't scheduled to see another one until they face Drew Pomeranz of the Padres next Thursday.
The Phillies' lineup got one boost Saturday, when third baseman Maikel Franco returned after missing one game. Franco's left elbow was sore after he was hit by a pitch in the ninth inning Thursday in Cincinnati.
Mackanin made Franco his cleanup hitter, moving Howard to fifth, behind Freddy Galvis, Cesar Hernandez and Odubel Herrera.
"Cesar likes hitting second," Mackanin explained. "I'm looking at every little thing I can do to make guys comfortable."
Mackanin didn't promise any immediate changes in the Phillies' bullpen, even though the team ERA out of the 'pen through four games was 12.66, the worst in the Majors.
"It still hasn't been long enough to fully evaluate," he said. "And our Triple-A team has only played two games, so it's hard to say anyone is throwing well there. It's going to take a little time, but we're not going to wait overly long."
Danny Knobler is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.