Gordon Lakey, the director of major league scouting for the Philadelphia Phillies, has been in New York to watch Beltran, who is in the final year of his contract. Meanwhile, the Mets have ramped up monitoring of Atlanta Braves and Phillies prospects, according to multiple major league sources.
The San Francisco Giants also had senior adviser Paul Turco watching Beltran for several days, a source said.
Sources have identified the Detroit Tigers and Boston Red Sox also as interested in Beltran, but one official indicated Detroit is focused on starting pitching, including San Diego right-hander Aaron Harang.
While ESPNBoston.com's Gordon Edes reported the Red Sox are unwilling to meet the Mets' high prospect demand for Beltran, ESPN The Magazine's Buster Olney reported Friday that the Red Sox remain aggressive in their pursuit.
Baseball sources also told Olney that the Texas Rangers are one of the teams that are serious about getting the outfielder.
A major league executive said he has been informed Beltran's preference in a trade is to remain in the National League where he is familiar with the pitching and would not be used as a designated hitter.
According to a source familiar with the pursuit of Beltran, the Mets may try to pry Randall Delgado or Arodys Vizcaino from the Braves, although obtaining either prospect appears overly ambitious.
Both are pitching at Double-A Mississippi. Vizcaino is the Braves' No. 3 prospect (No. 47 overall), and Delgado No. 4 (No. 50 overall), on ESPN Insider Keith Law's rankings list.
"I think any deal within the NL East will carry some sort of premium -- not necessarily one that is prohibitive, but something more than if sent elsewhere," an NL East executive said.
Beltran has full no-trade protection, but has indicated a willingness to relocate to a contending team. He used a midseason trade from the Kansas City Royals to the Houston Astros in 2004 as a springboard for slugging eight homers in 12 postseason games and setting up the seven-year, $119 million contract with the Mets that is set to expire at season's end.
With the Mets embarking on a three-city road trip after Thursday's series finale against the St. Louis Cardinals that does not return them to New York until Aug. 1, Beltran likely is playing his final home game at Citi Field today.
"I'm not really thinking ahead," Beltran said Wednesday, after delivering a two-run homer in the Mets' 6-5, 10-inning win against St. Louis. "I approach every day the same. I come to the ballpark, prepare myself and try to help the team any way I can. If it is, then it is. It's not there yet. I can't assume anything right now. I haven't heard anything from nobody, so right now I'm not concentrating on that."
Adam Rubin covers the Mets for ESPNNewYork.com.