Wiebe, who won his tour debut last year at the SAS Championship, completed 36 holes at 9-under 135.
Scott Hoch shot a 5-under 67 in round two and climbed into second place at 138.
"The eagle at No. 8 made up for my silly bogey there yesterday," Wiebe said. "Today, I didn't hit the ball great, but I played nice golf for the second day in a row. Any time you hole out a shot for an eagle, there's some luck involved but overall, I didn't make any bogeys so my mind was in the right place."
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