The pinched nerve leads to Isringhausen's right foot, which has begun to feel tingly and numb when he keeps it straight and tries to push off of it.
"It's just been festering for a while and then we finally got it checked out today," Isringhausen said. "It's finally gotten to the point where my foot's kind of numb, so it's time to take a few days off. Now's the time to do it, we have the extra guys now."
Isringhausen, who turned 39 on Wednesday, has thrown 46 2/3 innings this season, his highest total since 2007. In those innings, he's been a boon to the bullpen, posting a 4.05 ERA and counseling the team's younger arms. Though Isringhausen has already achieved his preseason goal of notching his 300th career save, he seemed confident he would return to the mound before season's end.
"It's a nerve thing, so we don't know how fired up it is, so it may take longer than I think to calm down," Isringhausen said. "The doctors said we have to be careful with it because then it can turn into a multiple months period thing trying to get it to calm down, so we just have to be a little careful with it."
Despite the recent setback, Isringhausen said he's been encouraged by his health this season, especially the way his troublesome right arm has held up. Once thought a long shot to make it through this season, Isringhausen said he's planning to pitch in the Majors again next year.
"If I can still throw, there's no reason why I shouldn't be doing this," Isringhausen said. "This is what I love to do. Barring something that happens between now and February, unless my wife tells me no, then I plan on pitching again."