© 2014 MLB Advanced Media, L.P. All rights reserved.

7/28/2014 8:26 P.M. ET

Amaro working the phones for trade possibilities

NEW YORK -- The Phillies' front office has been frustrated lately with its lack of success on the trade market, but it is still trying to complete at least one deal before Thursday's non-waiver Trade Deadline.

Phillies general manager Ruben Amaro Jr. traveled with the team to New York, where it opened a three-game series Monday night against the Mets at Citi Field. But Amaro was nowhere to be found before the game as he continues to call teams to find a trade partner for a group of players that includes right fielder Marlon Byrd and left-hander Antonio Bastardo.

"Am I expecting any [trades]?" Phillies manager Ryne Sandberg said. "I don't know one way or another. Just from what I hear, if there is [a trade], it'll be very late in the process."

Byrd and Bastardo remain the most likely Phillies to be moved, which is nothing new. Byrd was hitting .266 with 20 home runs and 60 RBIs entering Monday. His 20 homers are tied for eighth among right-handed hitters in baseball, which makes him valuable. Byrd can block trades to four teams, including the Mariners and Royals. He makes $8 million next season and he has an $8 million club option for 2016 that automatically vests with 600 plate appearances in '15 or 1,100 plate appearances in 2014-15, including 550 plate appearances in '15, which is a sticking point to some teams.

Left-hander Cole Hamels remains available, but the asking price remains extraordinarily high. This also is nothing new. The Phillies want to keep Hamels because he is the rare Phils player signed to a mega contract still in his prime, but they will consider trading him if they are absolutely blown away by an offer.

Cliff Lee and Jonathan Papelbon are unlikely to be moved by Thursday, but they could be traded in August if they clear waivers. Lee is owed at least $37.5 million following this season, while Papelbon is owed at least $13 million. A.J. Burnett remains a possibility, but he seems to be a second choice for teams still hoping for a pitcher like David Price, Jon Lester or Hamels. Burnett's player option could be worth more than $10 million next season. The money owed to Lee, Papelbon and Burnett has made trading them difficult.

Phils to hold workout for Cuban outfielder Castillo

NEW YORK -- It is no secret the Phillies are desperate for outfield help, so it is no surprise they are taking a closer look at Cuban outfielder Rusney Castillo.

MLB.com's Jesse Sanchez reports the Phillies will hold a private workout for Castillo on Tuesday. The Phillies were one of 28 teams that watched Castillo work out Saturday in Miami. Castillo, who is 5-foot-9 and 200 pounds, is known for his speed and considered a line-drive hitter with power.

The Phillies' current outfield situation is murky at best. Marlon Byrd could be traded before Thursday's non-waiver Trade Deadline. If that happens, it would leave Domonic Brown, Grady Sizemore, Ben Revere, Darin Ruf and John Mayberry Jr. as their remaining big league outfielders. They do not have anybody knocking down the door in the Minor Leagues, either.

Brown's .620 OPS entering Monday is 151st out of 156 qualifying hitters in baseball, and his .627 OPS as a left fielder is on pace to be the worst of any left fielder since 2002, when Chuck Knoblauch had a .582 OPS with Kansas City. Revere's .667 OPS entering Monday is 132nd in baseball, plus the Phillies would like a more defensively sound center fielder. Sizemore is trying to reestablish himself after missing the past few seasons because of multiple injuries, so the jury remains out on him. The Phillies have been trying to trade Mayberry, who is on the disabled list, for more than a year.

Phillies release outfielder Gwynn

The Phillies have released outfielder Tony Gwynn Jr., the team announced on Monday.

Gwynn was designated for assignment last Monday after appearing in 67 games for the Phils this season. He hit .163 with three RBIs, two stolen bases and 14 runs scored.

Over the course of an eight-year career with the Brewers, Dodgers, Padres and Phillies, Gwynn has appeared in 672 Major League games and hit .239 with a .621 OPS.

Todd Zolecki is a reporter for MLB.com. Joey Nowak is a reporter for MLB.com. Follow him on Twitter at @joeynowak. This story was not subject to the approval of Major League Baseball or its clubs.