Along with the stroke-play medal, the California native will be the top-seeded player in the match-play portion of the event, which begins Wednesday at The Orchards Golf Club.
The original field of 156 was cut to the top 64 based on the two rounds of stroke play. The cut was at 2-over at 146.
''Winning the medal is nice, but it doesn't mean anything from here on in,'' Jimison said. ''I'm in the tournament, but if you are No. 1 or No. 64, you still have to beat all the good players to win the trophy.''
Michigan State senior Eric Jorgensen shot his second consecutive 68 to finish at 136.
First-round leader Hunter Mahan, who tied the course record Monday with a 66, shot a 1-under 71 in the second round -- including a triple-bogey 7 on the 18th -- to finish in a four-way tie for third at 137.
Defending champion Chez Reavie, who struggled to a first-round 73, shot 68 Tuesday to easily qualify for match play. The runner-up last year, Danny Green, tied for 11th after shooting 69-70.
Jimison and J.J. Jakovac (138), representing Sacramento, Calif., won the team championship with a record-tying 271.
The tournament, in Macomb County, about 20 miles north of Detroit, is open to amateur golfers who do not have regular playing privileges on a private course.
The winner of the 36-hole final Saturday will receive an invitation to the 2003 Masters, providing he remains an amateur.
Second Round Scores:
Isaac Jimison, Orangevale, Calif.68-65--133 11-under
Eric Jorgensen, Grandville, Mich.68-68--136 8-under
Alan Hill, Spring Branch, Texas68-69--137 7-under
Lee Williamson, Crawfordsville, Ind.71-66--137
Hunter Mahan, McKinney, Texas66-71--137
Derek Tolan, Highands Ranch, Colo.68-69--137
Brent Wanner, Mashpee, Mass.69-69--138 6-under
J.J. Jakovac, Napa, Calif.69-69--138
Brady Stockton, San Ramon, Calif.72-66--138
Jay Choi, Cerritos, Calif.67-71--138
Danny Green, Jackson, Tenn.69-70--139 5-under
Burke Spensky, Huntington, W.Va.68-71--139
Jim Spagnolo, Fort Worth, Texas73-67--140 4-under
John Finnin, Crete, Ill.68-72--140
Michael Letzig, Richmond, Mo.73-67--140
Jon Lindstrom, Denver73-67--140
Justin Smith, Franklin, Pa.74-66--140
Billy Zihala, Little Rock, Ark.70-70--140
Henry Liaw, Rowland Heights, Calif.71-70--141 3-under
Chez Reavie, Phoenix73-68--141
Haymes Snedeker, Oxford, Miss.71-70--141
Casey Lubahn, East Lansing, Mich.70-71--141
Jason Harris, Clemmons, N.C.72-70--142 2-under
Chris Stroud, Groves, Texas73-69--142
Ryan Moore, Puyallup, Wash.72-70--142
Wren Fowler, Thomson, Ga.72-70--142
Justin Walters, Raleigh, N.C.73-69--142
Geoff Lound, Australia74-68--142
Bjorn Widerstedt, Sweden69-73--142
John Lieber, San Diego72-70--142
Keith Hendrickson, Syosset, N.Y.72-70--142
Kevin Tassistro, Rosemont, Ill.69-74--143 1-under
Chase Baldwin, Plant City, Fla.75-68--143
Timothy Kane, Simsbury, Conn.71-72--143
Crispin Fuentes, El Paso, Texas74-69--143
Neal Grusczynski, West Allis, Wis.71-72--143
Garrett Clegg, Bountiful, Utah72-71--143
Greg Kopf, Bay Harbor Island, Fla.75-68--143
Kevin Warrick, Valrico, Fla.72-71--143
Corey Huss, Woodstock, Ga.70-73--143
Gabe Alcala, Bastrop, Texas73-70--143
Luke Stephan, Hoffman Estates, Ill.71-72--143
Matt Anderson, Minneapolis72-72--144 Even
Drew Scott, Henderson, Nev.74-70--144
Brian Atkinson, Buffalo Grove, Ill.71-73--144
Richard Dukelow, Chicago72-72--144
John Cassidy, Yelm, Wash.71-73--144
Greg Uberuaga, San Diego76-68--144
Fernando Mechereffe, Brazil72-72--144
Russ Cunningham, Dewitt, Mich.74-70--144
Brett Jones, Paducah, Ky.69-76--145 1-over
John Schones II, Tucson, Ariz.72-73--145
Mike Miller, Knoxville, Tenn.76-69--145
Brian Hughes, Portland, Ore.74-71--145
J.J. Wall, San Antonio69-76--145
Steve Lohmeyer, Dayton, Ohio72-73--145
Josh Green, Toms River, N.J.78-67--145
Jake Grodzinsky, Cornville, Ariz.75-70--145
Kurt Watkins, Chandler, Ariz.73-72--145
Justin Jennings, Lunenburg, Mass.77-68--145