Rick Jones of Wood River is asking federal Judge Phil Gilbert for more time at the Mayo Clinic in Minnesota.
Jones, who pleaded guilty to tax evasion in January, has filed a motion for an extension of time to remain outside the limits of southern Illinois.
He is scheduled to be sentenced by Gilbert on May 7 in U.S. District Court. He has admitted to dodging $1.2 million in 2003 taxes. He also admitted that he evaded a similar amount before and after 2003.
"Mr. Jones has advised undersigned that said medical examination is taking longer than anticipated," wrote Jones's attorney James Martin of Armstrong Teasdale in St. Louis on April 6. "He now expects to return home no later than Monday, April 13, 2009."
Jones is scheduled for trial in a Madison County divorce case he filed against his wife, Dorothy Jones, on April 13, before Associate Judge Duane Bailey.
Jones faces up to five years in prison, but can earn a shorter stretch if he cooperates "fully" with the government, his plea agreement states.
On sentencing day, he is required to pay restitution of $1,207,415.82 to BP Amoco North America, on top of a promise to pay $2.4 million in federal income taxes for 2002 through 2005.
In his plea agreement, he stipulated that his company, Triad Industries, received money from BP Amoco to clean up refinery pollution but spent it in other ways.
Jones has posted $100,000 bond for release pending sentencing.
Gilbert granted Jones's request to travel to the Mayo Clinic. Jones previously indicated he would return on or about April 8.
Jones also is represented by William Stiehl, Jr. of Belleville.