First indications are that Tiger Woods’ return has increased television viewership of the Masters by 50 percent.

The Nielsen Co. said that ESPN’s coverage of the Masters’ first round on Thursday had a 3.6 rating in an overnight measurement of the nation’s biggest markets. That’s 50 percent more than the similar measurement for last year’s opening day, and 80 percent more than it was in 2008.

The company is expected to release viewership estimates accounting for all of the country later on Friday.

ESPN covered Woods’ first tee shot live within “SportsCenter” more than two hours before regular coverage started on Thursday. Nielsen said its audience was double what it gets on a typical Thursday afternoon. But the .8 rating was much smaller than it got later in the afternoon.