Halladay was examined Tuesday by Michael G. Ciccotti, the Phillies medical director, at Jefferson Hospital. To fill Halladay's spot on the 25-man roster, catcher Erik Kratz has been recalled from triple-A Lehigh Valley.
"We hate to have him down, but it's not something that requires anything other than rest," Proefrock said before Tuesday's game at Citi Field against the New York Mets. Proefrock said there was no structural damage in the shoulder.
Known as one of the hardest working players in the baseball, all Halladay can do now is rest.
"He is all about winning and playing every day and puts in everything he can for the team," rightfielder Hunter Pence said. "You feel bad for him and happy it's not too serious."
"Hopefully, it doesn't take six to eight weeks. Hopefully, it will take shorter," centerfielder Shane Victorino said.
Pitching coach Rich Dubee said he was relieved that the injury wasn't more serious.
"It could have been the labrum. It could have been the rotator cuff," Dubee said. "If there is good news from an injury, this is probably good news."
Dubee had his suspicions that something was wrong for some time.
"I've thought since spring training that there was an issue," Dubee said. "The ball just hasn't been accelerating through the zone the way his stuff does."
Halladay had to leave after the second inning of Sunday's 8-3 loss in St. Louis with soreness in the back of his right shoulder. He is 4-5 with a 3.98 ERA.
Halladay has had five previous trips to the disabled list, the most recent in 2009 as a member of the Toronto Blue Jays with a strained right groin. Two of the trips were for shoulder issues, both in 2004.
Halladay, who turned 35 on May 14, has been a workhorse. Beginning in 2006, he has thrown 220 or more innings in each of the previous six years.
"He is 35 and has thrown a lot of bullets and sooner or later it will catch up with you, and I think he's at the point where if he steps back a little bit, you will see that he will still be a dominant pitcher," manager Charlie Manuel said.
Vance Worley, who is on the disabled list with right elbow inflammation, threw a bullpen session Tuesday and said he's coming along well. Worley could replace Hallady in the rotation. With an off day on Thursday, it buys the Phillies some time.
In addition, there are triple-A options such as righthander David Bush, the former Milwaukee Brewer who is 4-3 with a 2.61 ERA at Lehigh Valley.
Bush has a June 1 opt-out of his minor-league contract. But according to Proefrock, it is only for a major-league job and that he would have to be put on a 25-man roster.
Doc on the DL
Here are Roy Halladay's previous stints on the disabled list:
May 28-June 11: Right shoulder tendinitis. He went 2-3 afer his return.
July 17-Sept. 20: Right shoulder fatigue. He went 1-1 after his return and finished the season 8-8 with a 4.20 ERA.
July 9 through the rest of the season: Fractured left tibia. He finished 12-4 with a 2.41 ERA
May 11-30: Appendicitis. He went 12-5 after his return and finished 16-7 with a 3.71 ERA.
June 13-28: Strained right groin. He went 7-9 after his return and finished 17-10 with a 2.79 ERA.
Contact Marc Narducci at 856-779-3225 or firstname.lastname@example.org. Follow @sjnard on Twitter.
Daily News staff writer David Murphy contributed to this article.