Colin Kaepernick

San Francisco 49ers quarterback Colin Kaepernick will opt out of his contract, but the Browns won't come calling.

(Tony Avelar)

INDIANAPOLIS, Ind. -- The Browns might soon be heartbroken by Jimmy Garoppolo, but they won't pursue 49ers quarterback Colin Kaepernick on the rebound despite Hue Jackson's heavy interest last year, a league source told cleveland.com.

Kaepernick's new agents from Select Sports Group sent a letter to all 32 teams notifying them that Kaepernick will opt out of his contract on Thursday and become an unrestricted free agent, according to NFL Network and other reports.

Jackson, who loved Kaepernick coming out of the draft in 2011, wanted to acquire him last off-season, but the 49ers retained him. The Browns signed Robert Griffin III instead, but he missed most of the season with a fractured shoulder, and the Browns don't think they can count on him because of the durability issue.

But they won't be going back to the Kaepernick well, the source said.

The Browns will be in the market for a veteran quarterback, although ESPN's Adam Schefter reporte Wednesday that "Jimmy Garoppolo is not going to be traded'' by the Patriots.

The Browns are still expected to try to pursue Garoppolo, and will probably find out at the combine if the Patriots are serious about keeping him. If they are, the Browns will have to turn their attention to other quarterbacks -- Buffalo's Tyrod Taylor if he's released, Cincinnati's A.J. McCarron in a trade and Tampa Bay's Mike Glennon as a free agent.

But Kaepernick isn't in their plans, despite reports last year that he really wanted to play for Jackson, and Jackson's strong interest in him.

Kaepernick went 1-10 last season, but put up his best numbers since 2013, including a 90.7 rating that ranked 17th in the NFL.

In addition to veteran quarterbacks, the Browns will strongly consider drafting a quarterback in the first round. Top candidates are Mentor, Ohio native Mitch Trubisky and Deshaun Watson.