Minnesota United might be looking at yet another version of a back-line when the team travels to the Chicago Fire for a 7:30 p.m. Saturday match.

Center-back Brent Kallman rode a stationary bike and practiced separately on the sidelines from his teammates on Wednesday at the National Sports Center. Coach Adrian Heath said the defender is "day-to-day" dealing with lingering injuries.

Kallman sprained his MCL on June 24 against the Vancouver Whitecaps FC and has since played in just three of the past seven matches, including this past Sunday's game at Seattle.

The back-four combination at Seattle featured team captain Francisco Calvo shifting to left-back. He was slotted in for Ish Jome, who had taken on the role in an emergency situation after starter Marc Burch went out with his bilateral sports hernia surgery.

"The fact that Francisco has played there before is a big help, and it's another more experienced body," Heath said. "That was why I changed it at the weekend. If ever there was a game that we were going to need experience on the field, I thought that was it in Seattle. Because Ish has done OK at home, but I wanted to make sure that we had a lot more experience on the field [on the road]."

That change also made Kallman's versatility a real boon, as the naturally right-footed player can also play as a left-sided center-back. Heath said while he would prefer his players play on their dominant side, sometimes it can be easier for a right-footed left-side center-back to pass to a left-back.

Some possible good news is that center-back Joe Greenspan, who broke his nose and endured his third concussuion of the season July 19 against the Houston Dynamo, is "just about ready to start work again," according to Heath. Greenspan has been taking partial part in team practices, working on the sidelines when not with the group. He's been out for four matches.

No rush

Forward Christian Ramirez has been dealing with a hamstring injury, his first muscle injury in his career, since the July 29 match against D.C. United. Ramirez, who has been practicing with the team the past few days, ducked out of Wednesday's session early.

Heath said the team's leading scorer is still "day-to-day" and "the only time he'll play is when he's 100 percent."

The reason the coach is so comfortable giving his star player time to fully recover instead of risking exacerbating the injury is because of rookie forward Abu Danladi.

"I know he missed a couple of chances (against Seattle), but I was quite pleased with some of the stuff Abu did," Heath said.

Heath said looking back at the recent homestand, Danladi could have scored one or two goals every match. Even though the shots aren't going in, or even on frame, Heath said he doesn't want to put Danladi under too much pressure and make it a mental block.

"He made good runs. He got himself in good spots. If he was in a position where he wasn't getting in them spots, we would have a lot more to work with," Heath said. "He's got to be a little bit more composed when he gets in there. And if he brings that composure to himself, he's got a chance of scoring a lot of goals."

Kadrii still absent

Midfielder Bashkim Kadrii missed his second consecutive practice Wednesday for "personal reasons." Heath was unsure of the Denmark native's return but was "hopeful" it would be soon.

Kadrii, 26, has played in 11 matches with five starts for the Loons this season, on loan through the season from FC Copenhagen, and last played July 19. He has yet to score or assist in MLS play.