FORT MYERS, Fla. — Hours after Red Sox owner John Henry said talk of collusion in free-agent negotiations was “ridiculous,” his team made a splash by reaching agreement with slugger J.D. Martinez on a $110 million, five-year contract.

About half the 166 players who exercised free-agency rights in November remain unsigned.

“There are a lot of factors, I think, driving it, and I think they’ve all been identified,” Henry said Monday as Boston began full-squad workouts. “There’s a lot of factors that have driven this offseason, and you just can’t expect every season to be a feeding frenzy, so to speak.”

Jake Arrieta and Mike Moustakas were among the free agents still looking for a place to play.

“This one, it’s surprised me,” he said of the slow pace of agreements. “I think it’s surprised all of us in baseball.” ”But, I think probably next year will be quite different.”

By late afternoon, word had spread that Martinez was headed to the Red Sox.

Next year’s free-agent class includes Bryce Harper, Manny Machado and Josh Donaldson, plus possible Clayton Kershaw.

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