Ryan Dempster goes on DL

CHICAGO -- More evidence of the Chicago Cubs' extremely difficult season emerged Monday as they not only lost their best pitcher to injury for at least two weeks, they lost one of the best pitchers going in the game right now.

Right-hander Ryan Dempster, who currently has a scoreless streak of 22 consecutive innings, was placed on the 15-day disabled list with tightness in his latissimus dorsi muscle.

The Cubs recalled left-hander Scott Maine to take his place on the roster, with Randy Wells scheduled to take Dempster's spot in the rotation Wednesday against the White Sox.

Potentially the club's best trade chip as the non-waiver trade deadline approaches, Dempster is expected to miss only a few starts and should be back well before the July 31 deadline.

"We're going to play it conservatively with this one with the way he's throwing," said president of baseball operations Theo Epstein. "We want to nip this one in the bud to make sure it doesn't turn into a strain or something like that. It's unfortunate because he was throwing as well as anyone in the game."

Dempster said the issue first cropped up three outings ago against the Milwaukee Brewers, the first of his three consecutive scoreless outings. The tightness behind his right shoulder has gotten progressively worse ever since.

"It got harder to pitch through it," Dempster said. "I'm a pretty good judge of my body, when it tells me it's ready to go again, I'll be ready to go again."

The Cubs seem confident that because the injury is not considered serious, it will not affect Dempster's trade value. Even if the injury lasted longer than expected, major league rules do not prohibit a player from being traded when he is on the DL.

"I don't want to talk specifically about Dempster in that context, but I will say generally when players have these minor injuries, it's typical to wait until they come back and establish health before there's trade talks," Epstein said. "That's the fair thing to do."

Dempster has a 2.11 ERA, but a lack of run support and help from the bullpen has left him with a 3-3 record after 12 starts. This is his second stint on the disabled list after missing two starts with a quadriceps injury earlier in the season.

"I won't play catch for a few days," Dempster said. "I'll just let it get totally rested up and healed up, see where we're at. It's gotten better in the last couple days, which is a good sign. That means that it's loosening up. Just get it back and get it ready. When it's ready, it's ready and I'll go out there and pitch."

Always quick with a one-liner, Dempster took the injury in stride, which is easier to do with that 22-inning scoreless streak.

"I wanted to sit on that for a little while, make Orel Hershiser sweat," Dempster said.

Hershiser, who was one of the ESPN broadcasters for Sunday night's game against the Boston Red Sox, has the record for consecutive scoreless innings at 59.

In another roster move by the Cubs on Monday, Geovany Soto was activated from the disabled list at game time with Welington Castillo sent down to Triple-A Iowa, as the team elected to not go with a previously mentioned plan of carrying three catchers.