Minnesota United FC will not sign trialist Abdoulaye Diallo, who had trained with the team for the past month.

Diallo, 24 a center-back from Senegal, was not at practice Tuesday at the National Sports Center. Coach Adrian Heath confirmed after the session that the defender wouldn't be joining the squad full time. He began practicing with the team March 28.

"No, he's not with us anymore," Heath said. "We decided against doing something with him. So we will see where we go from here."

Diallo would have required an international roster spot, and United didn't have a spot open ... until recently.

The club confirmed that Brazilian midfielder Ibson has been approved for a green card, and thus no longer requires an international spot.

So, right now, United has nine international slots (it traded one to Colorado along with Mo Saeid back in that March 31 transaction) and eight players taking those up: John Alvbage, Francisco Calvo, Vadim Demidov, Jerome Thiesson, Rasmus Schuller, Bashkim Kadrii, Johan Venegas and Abu Danladi.

Hypothetically, that leaves one spot open for a potential move. However, midfielder Bernardo Anor, who has been on the disabled list all season with a leg injury, would need an international spot once he comes off the DL. The club said Anor is also working toward a green card but has not received one yet.

United has until May 8 before Major League Soccer's primary transfer window closes. The next window is from July 10 to Aug. 9.

"It's an ongoing process," Heath said of potentially adding more players before the first deadline. "I don't think that you've ever completely got the perfect squad because you're always looking to improve as you go. The most important thing is, at this moment in time, is the group we have here, working hard with them and trying to make them better. I think that's what's happening.

"But if something [came up] that we felt would benefit the club in the short, medium and long term, then we would do something."

Back to those guys who are on the team now: Defender Brent Kallman practiced a bit along with the other starters Tuesday morning. He came off in the 66th minute of United's 1-0 win against the Colorado Rapids on Sunday at TCF Bank Stadium with a calf injury that aggravated a lingering hip injury.

The center-back, like most of the starters (except winger Kevin Molino, who worked on a stationary bike), participated in the first few minutes of practice before the bench players finished out the session with some harder training.

"He's feeling a little better," Heath said of Kallman. "He only joined in on a little bit of the light stuff in the morning, so we think he's going to be OK. Just a case of getting him through the first couple of days."

Heath said Kallman has had his hip injury for "quite a while." Trainers will continue to monitor the "ongoing" recovery process, the coach said, but it's "not too bad."

Heath said midfielder Rasmus Schuller's return is still pending. Schuller endured a hip flexor injury in the April 15 match at the Houston Dynamo and didn't make the match-day squad on Sunday despite practicing last week.

Schuller did practice with the team Tuesday but had to tap out a bit early with some pain.

"We'll have a better idea today," the coach said. "He felt it a bit this morning. He's got a sore, tender area, and when he opens it up, he aggravates it a little bit. So it's one of them that we might just have to give him four or five days of compete rest. Or we'll see if he can monitor through.

"But as most players do, they want to carry on training because they know how important it is."

United plays the San Jose Earthquakes at 7 p.m. Saturday at TCF Bank Stadium.