Wood, who has a blister on his right index finger, was placed on the DL retroactive to June 9.
Wood, who is 1-3 with a 3.25 ERA in 24 games this season, has had to deal with blister problems before in his career. On Sunday, he tried to warm up in the bullpen but had to stop pitching due to the blister. Wood said he has dealt with the problem off and on for about a month.
"It's not the first time we've dealt with it, but we had been dealing with it fairly well," Wood said Sunday. "I thought we turned the corner. I just think the humidity the past couple weeks has made it worse."
Baker, who has been on a rehab stint at Triple-A Iowa, has been on the DL since May 29 with a strained left groin. He was joined in Iowa for rehab by outfielder Reed Johnson, who is out with back spasms. But Johnson's return was slowed after he was hit in the head by a pitch Saturday and taken to a Des Moines hospital for examination.
Johnson, who is hitting .367 in 60 at-bats this season, is back in Chicago on Monday to be examined by team doctors, and his return is uncertain.
Outfielder Alfonso Soriano began his rehab for a strained right quad on Sunday in Iowa. He is eligible to come off the DL on Wednesday.
Bruce Levine covers the Cubs for ESPNChicago.com and ESPN 1000.