Four players _ including 2007 champion Hunter Mahan _ were tied for fourth at 7-under.
Charley Hoffman, who held the first-round lead after a 61 on Thursday, followed that with a 73 in a round that included three bogeys and a double-bogey.
Watson, whose last victory came in the 2012 Masters, has played well in this event often. He’s finished in the top 15 four times in six previous starts, including a second-place finish last year.
The South African made six birdies, a double bogey and a bogey, leaving him at 12-under 132 halfway through the European Tour event. Els, a two-time winner of the British Open and U.S. Open, opened with a 63 Thursday.
He is followed by Matthew Baldwin of England (69) and Alexander Levy of France (68). Defending champion Danny Willett of England shot a 65 for the day’s best round and is tied for fourth place with Bernd Wiesberger of Austria.
GLENVIEW, Ill. (AP) _ Craig Stadler birdied five of his first 11 holes to jump into a share of the lead with Duffy Waldorf and Bernhard Langer at 5-under-par 67 in the rain-delayed Encompass Championship at North Shore Country Club.
There were 23 players left on the course when play on the 54-hole tournament was suspended by darkness. Stadler, who didn’t start until after a 3-hour, 28-minute delay for severe weather was in the next-to-last group to finish.