Howard was placed on the 15-day disabled list with left knee inflammation over the weekend after receiving a cortisone shot in his knee last Sunday.
“We’ll see what happens [Monday] to get a better understanding of what’s going on inside of there and then we’ll address it with either surgery or any other kind of injections,” Howard said on Saturday. “Right now, it’s too early to tell. Once we find out, we’ll look at it and see what will be the best thing.”
Howard, 33, is batting .266 with 11 home runs and 43 RBI in 80 games this season. Howard is in the second season of a five-year, $125-million extension signed in 2010. The Phillies are 43-46, 7.5 games behind the first place Atlanta Braves in the National League East. The Phillies recalled outfielder Darin Ruf to replace Howard on the active roster.