Prior to Howell, the top nine remained the same. Tiger Woods, who hasn't played since the Masters, stayed put at No. 1 and was followed by Phil Mickelson, Retief Goosen, Vijay Singh, Jim Furyk, Ernie Els, Sergio Garcia, David Toms and Adam Scott.
Howell moved to 10th, while Luke Donald and Jose Maria Olazabal were each down a spot to 11th and 12th respectively. Henrik Stenson maintained the 13th position this week.
Chad Campbell dipped two places to 14th with South African Tim Clark slipping one to 15. Australian Stuart Appleby moved forward two places to 16th, while Geoff Ogilvy and Chris DiMarco each fell two to 17 and 18.
Darren Clarke remained 19th, while reigning U.S. Open champion Michael Campbell climbed a pair of spots to round out the top 20. To make room for him, Davis Love III tumbled three places to 23rd.
Jeff Maggert claimed the FedEx St. Jude Classic in Memphis and in doing so flew up from No. 144 to No. 75 in the new rankings.