Furbush was removed from Tuesday's game in the seventh inning after feeling a twinge in his left shoulder muscle on the second pitch he threw. He then threw about 15 pitches in an indoor hitting cage after the Mariners' 9-6 win over the Royals and didn't feel any problems. Furbush then appeared to be OK playing catch on the field at Kauffman Stadium on Wednesday afternoon.
But when pitching coach Carl Willis and trainer Rick Griffin had him follow that with 15 pitches off the mound in the cage again, he felt the discomfort return when he unleashed his final few throws at full speed.
"It was the last few when I amped up a little to see where I was at, and I felt it again at the same spot," Furbush said. "It wasn't worse, it was just there. Just a little discomfort. Rick looked at me and he thinks it's probably the muscles in that back area are fatigued and I just need to give it a break. Nothing serious, just take two weeks off and ready to go again.
"I just have to get better and be back before you know it. I see this as just a minor speed bump in the road. I'll just take it one day at a time and get back as soon as I can."
Delabar, a right-handed reliever, hadn't even left town yet and will rejoin the team immediately. He was optioned to open a roster spot for starter Blake Beavan, who got the victory on Tuesday.
Normally a player who is optioned can't be recalled for 10 days, but that rule is waived if an injury replacement is needed.
Furbush has been outstanding in a relief role this season, going 4-2 with a 2.17 ERA in 34 appearances while holding opposing batters to a .148 average. He'd allowed just 19 hits in 37 1/3 innings with 11 walks and 47 strikeouts.