DURHAM, N.C. (CBS SF) – Free agent quarterback Peyton Manning underwent a physical and threw passes in front of San Francisco 49ers coaches this week, including head coach Jim Harbaugh, according to published reports.

Manning worked out for the 49ers Tuesday on the campus of Duke University in North Carolina with Harbaugh and offensive coordinator Greg Roman on hand to watch the throwing session, according to ESPN’s Chris Mortensen and Adam Schefter. The coaches reportedly left very impressed with Manning’s recovery from a series of neck surgeries.

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On Friday, Denver Broncos executive John Elway and coach John Fox traveled to North Carolina to see Manning work out, while the Miami Dolphins dropped out of the running to sign the NFL’s only four-time MVP. Denver has been considered a favorite to sign Manning, with Tennessee and Arizona also pursuing the former Indianapolis Colts star.

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Manning’s uncertain health led Indianapolis to balk at paying a $28 million roster bonus to the 35-year-old quarterback, which in turn started a race for the most prized free agent of the off-season and maybe ever.

The Colts hold the first overall pick in the upcoming NFL draft, and were expected to target Stanford quarterback Andrew Luck.

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