WEST PALM BEACH, Fla. — The Washington Nationals’ efforts to sign Anthony Rendon to a contract extension led to an offer late last month, according to people with knowledge of the negotiations. The timing of the offer coincided with fellow third baseman Nolan Arenado signing an eight-year, $260 million extension with the Colorado Rockies. The Nationals’ offer, terms of which were not disclosed, was rejected by Rendon and his representation.

The offer was first reported by NBC Sports Washington, who learned of the latest developments from Rendon. The 28-year-old has been one of the best at his position in recent years, and the Nationals have repeatedly expressed interest in keeping Rendon beyond 2019. He is due to be a free agent at the end of the coming season. Rendon noted to NBC Sports Washington that negotiations have “come to a halt lately,” but he added that talks will continue. A person familiar with the negotiations said Wednesday that they expect more discussions now and into the regular season, which begins for the Nationals on March 28.

Rendon’s negotiations come as some premier third basemen are setting their futures ahead of free agency. Arenado, 27, is widely considered the league’s top player at the position and may have set a new bar with an average annual value of $32.5 million. Alex Bregman, 24 and another MVP-caliber third baseman, agreed to a six-year, $100 million extension with the Houston Astros on Tuesday night. Arenado’s deal accounts for his final year of arbitration eligibility and the following seven seasons. Bregman’s extension will kick in for 2020 and cover his three years of arbitration eligibility and the first two seasons he would have been a free agent.

There is a belief that a slow labor market across the past two winters has led prominent players to seek extensions instead of free agency. Manny Machado did not agree to a deal with the San Diego Padres until Feb. 19, and Bryce Harper agreed to join the Philadelphia Phillies on the final day of that month. Many other players had trouble finding teams or even offers this winter. Starting pitcher Dallas Keuchel and reliever Craig Kimbrel are still available as Opening Day nears.

Rendon has appeared open to an extension with the Nationals, the only organization for which he has played, even if agent Scott Boras has a history of bringing clients to the open market. Rendon pushed back on that last month, saying he pays Boras and not the other way around, indicating that he will not follow any past trends. There is also a recent example of a Boras client reaching an extension before free agency with the Nationals — starting pitcher Stephen Strasburg, Rendon’s teammate with Washington, signed a seven-year, $175 million extension in May 2016. He would have become a free agent in about six months.

“I work for Anthony,” Boras said in a phone interview Feb. 21. “He makes all the decisions and has directed me to listen and work with the Nationals regarding any contract discussions they choose to advance.”

While some players may not want to discuss contracts during the season, that wouldn’t bother Rendon. He wants to be involved in the process and is open to talking with the Nationals throughout the coming months. They are the only team who can negotiate with him at the moment — and it will remain that way until after the World Series — so there is a lot of time to maximize that exclusivity.

But that doesn’t mean there isn’t urgency for the Nationals. They have made one offer, they see other teams locking up their star third basemen, and they know Rendon is an even more important piece in the post-Harper era. He is a middle-of-the-order hitter, with an on-base-plus-slugging percentage over .900 in the past two seasons, and a strong fielder at one of baseball’s most valuable positions. They don’t want to let that get away.

“I’ll talk to Anthony about being here for as long as he wants to talk about it,” General Manager Mike Rizzo said last week.

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