CINCINNATI -- Geoff Blum had seemed to be progressing well at extended Spring Training and D-backs manager Kirk Gibson remained cautiously optimistic about the third baseman's return, barring any setbacks.
Prior to Thursday afternoon's game against the Reds, Gibson revealed the latest news on Blum. And it isn't so optimistic.
Blum, who's on the disabled list retroactive to March 22 with right knee inflammation, will likely have surgery on his knee next week and could be out an additional six to eight weeks, if not longer.
"You don't really know until they go in there and see what they're up against," Gibson said. "He played in one game and didn't feel so well. I hope he can rehab and get back and be the guy we want him to be. We didn't see this coming. You don't always get what you want."
Arizona has been able to make do without Blum so far this season. One major reason why is the emergence of Ryan Roberts, who has reached base in eight of his nine starts and entered Thursday batting .375 in that stretch.
"We have 25 guys to play with," Gibson said. "That's what a team and an organization is all about. We'll just have to deal with it with other people."
In more positive rehab news, left-hander Zach Duke, on the DL since March 30 with a broken throwing hand, could begin throwing bullpen sessions next week when the D-backs return home.