David Duval and Scott Verplank head the field at halfway in the Byron Nelson Classic in Texas.

Duval fired a second-round five-under-par 65 to join first-round leader Verplank on 11 under after the latter carded a 67.

Robert Damron and Vijay Singh both enjoyed 64s to move up to third and fourth on 10 under and nine under respectively.

Rochdale-born Edward Fryatt's 65 was enough to push him up to fifth on eight under.

Tiger Woods, competing in his first tournament since his historic Masters win, is back in joint-10th after a 68 left him on six under alongside Sweden's Jesper Parnevik, the defending champion having shot a 64.

Parnevik's compatriot Gabriel Hjertstedt is just one shot back after a 69 while Spain's Sergio Garcia sneaked inside the cut on one under after a 68.