Ruf cannot return for 10 days unless he replaces an injured player. He batted 11 times since his May 21 recall and was 1 for 10 with a homer.
"It's just to get him a number of at-bats," Sandberg said.
The roster shuffle gave the Phillies 13 pitchers for the time being. Sandberg said they will stay at that level for at least a few more days. He was without four relievers Sunday. Mike Adams, less than a year removed from shoulder surgery, complained of soreness after a 27-pitch outing Friday.
Sandberg is wary of the heavy workload for his primary relievers.
"It's too early in the season to mess with them," he said. "They've pitched a lot in the last week."
So Ruf was the one to go. Neither John Mayberry Jr. nor Reid Brignac has options remaining. Cesar Hernandez, who started at second base Sunday, is the lone reserve infielder. Both Domonic Brown and Ben Revere have options, but the Phillies were not about to demote a piece of their starting outfield.
The Phillies invited about a dozen prospects to Citizens Bank Park for a Saturday morning workout, and Nick Gordon, one of former Phillies pitcher Tom Gordon's sons, was among them. It is unlikely, though, that Gordon falls to the Phillies at No. 7 in the draft Thursday.
Top front-office executives were present for the 7 a.m. session. The Phillies typically bring potential picks to Philadelphia before the draft so their entire scouting staff can make one last evaluation.
Gordon has long been a favorite of the Phillies, but his stock has risen in recent weeks. Baseball experts do not expect Gordon to drop lower than No. 5, the Minnesota Twins' pick.
The Phillies could have their future shortstop in J.P. Crawford, the 16th pick in last summer's draft, who has impressed at single-A Lakewood. That would not stop them from picking Gordon, an 18-year-old shortstop at Olympia High School in Florida.
The strength of the draft is college pitching, and the Phillies have a definite need for inventory.
The Phillies and Mets were the first teams to play three consecutive games of 11 or more innings since Seattle and Toronto did it in September 1991. ... Cole Hamels passed Curt Schilling for fourth place on the Phillies' all-time strikeouts list. He has 1,561, just 25 behind Chris Short for third place. ... Lefthander Jeremy Horst was designated for assignment to clear space for Jimenez on the 40-man roster. Jimenez passed him on the depth chart.