A baseball player soon might sign for almost $300 million, but that player will not necessarily be Bryce Harper or Manny Machado.



If Rockies third baseman Nolan Arenado foregoes his right to become a free agent, he probably will want at least $250 million, a number he might approach if not exceed next winter on the open market.



And if Arenado gets such an extension without the benefit of competitive bidding, it will be a potentially game-changing development, strengthening the argument for Harper and Machado to get lucrative 10-year contracts, elevating the market for future free agents, forcing teams that coveted Arenado to devise new plans.



Rockies owner, chairman and CEO Dick Monfort expressed optimism on Saturday that the team would reach a long-term agreement with Arenado, telling MLB.com, “I think we’ve gotten it to the point where we’re to the finals. We’re to the crescendo.”



A new deal for Arenado, 27, would...