MINNEAPOLIS (AP) -- Minnesota Twins first-baseman Justin Morneau says there is no timetable for his return from a concussion, and reliever Jose Mijares will miss four weeks with a torn meniscus in his right knee.
Morneau says he's "making progress and seeing some positive signs."
The former Most Valuable Player says he still experiences symptoms from the concussion, specifically while running.
He was injured sliding into second base against the Toronto Blue Jays on July 8.
"At first it was wake up in the morning, feel good for about 10 minutes, and then the rest of the day not so great," Morneau said. "It's gone to wake up in the morning, feel great, get here, feel good, start doing stuff, feel good, then get home and the symptoms come back."
The Twins originally hoped to have Morneau work out with the team in Chicago earlier this week, but manager Ron Gardenhire said the team has decided to back off and allow Morneau to work out at his own pace.
"Putting him in a situation where he could jeopardize his season, his career, his livelihood, we're not going to do that. It's just not going to happen," Gardenhire said.
Morneau was hitting .345 with 18 home runs and 56 RBIs before the injury.
The tear in Mijares' meniscus was discovered during an MRI exam Friday. The lefty injured the knee covering first base during Wednesday's loss to the White Sox and will require surgery.
Gardenhire said Ron Mahay and recently recalled lefty Glen Perkins will have their situational bullpen roles expanded to include late-inning appearances. The manager also said he's confident the Twins have plenty of right-handed relievers to face left-handed hitters.
Mijares is 1-1 with a 2.81 ERA this season.