A Wright County official will be the latest in a series of election officials to testify in Coleman's trial.
Coleman's legal team is trying to show that election officials in different areas counted similar ballots differently and therefore more ballots should be counted.
Coleman wants the court to open and count more ballots in the hopes he can erase Democrat Al Franken's 225 vote lead following the statewide recount.
The Coleman camp is also asking the three-judge panel to reconsider its Friday ruling. The panel ruled 12 of 19 categories of absentee ballots that Coleman wanted to introduce did not comply with Minnesota law and would not be counted in the final tally.
The judges excluded categories such as ballots submitted by voters who weren't registered and ballots that arrived late from people who lived overseas.
Coleman attorney Ben Ginsberg says the campaign is asking the court to reconsider its ruling because the panel has eliminated some categories under consideration that included about 100 ballots the state canvassing board has already counted:
"They won't be arguments about the categories. They will show ballots that... would be illegal under the court's order, that were in fact legally cast and counted ballots... put in by the canvassing board or in a couple of instances one for the intervenors who were let in earlier this week," Ginsberg said.
Lawyers for Democrat Al Franken were happy with Friday's ruling because they asked the court to strictly limit the categories of ballots under consideration.
As a result of that ruling, Coleman's campaign may introduce about 3,500 ballots, which is down from the 12,000 that Coleman orginally wanted the court to consider.
Marc Elias of the Franken campaign predicts Coleman won't be able to open and count the full 3,500 ballots.
"This universe is contracting. It is continuing to contract," Elias said. "The Coleman campaign started with it, wanted the 12,000 then it became 4,800. Now it's south of 3,500 and will continue to contract from there."
On Monday, the court heard testimony from several voters who believed their absentee ballots were wrongly rejected. The court session lasted less than 20 minutes.
Also Monday, Franken appeared for the first time as Sen.-elect Franken at a series of public meetings with several Minnesota mayors to talk about how the economy is afffecting their cities.
Court begins at the Minnesota Judicial Center in St. Paul Tuesday at 9 am.