Beyond that, Furbush said he would take each bit of news as it comes and not make any assumptions, although Seattle manager Lloyd McClendon wasn't so optimistic.
"Highly unlikely that he will pitch again this year," McClendon said.
If that's the case, Furbush finishes with a 2.08 ERA in 33 games and 13 holds, plus a left-handed opponent batting average of .105 (4-for-37). He has been on the disabled list retroactive to July 8 with biceps tendinitis, and the shoulder problem emerged during his DL stint.
Then again, Furbush wasn't quite ready to call it a season and said he was encouraged that Khalfayan said it was not a full tear and did not recommend surgery.
"I just look at it as a small bump in the road for me," Furbush said. "We're going to deal with this and hopefully take care of it and be back before I know it. It's just one of the things that you've kind of got to deal with, and I'm not going to look too far ahead and not too far behind.
"Honestly, when I heard the news, it doesn't feel that bad, so that's a good thing for me."
• The Mariners placed another lefty reliever, Joe Beimel, on the 15-day DL with left-shoulder inflammation Friday and recalled lefty Rob Rasmussen from Triple-A Tacoma.
"It's hard for him to function," McClendon said of Beimel, 38, who's given up eight earned runs in his last 2/3 of an inning over four appearances. "He can't get extension. He's been squaring the ball and elevating in the zone. So I think this was a necessary move to try to get him right."
• McClendon said lefty starter James Paxton, who's been on the DL since late May with a tendon strain in his left middle finger, is scheduled to make a rehab start Sunday for the Triple-A Rainiers in Tacoma. McClendon said the plan is for Paxton to get to 45-50 pitches in that outing, ramp up to 65-70 in the next rehab start, "and then we'll see."