Worrell was 3-3 with a 2.15 ERA and 80 strikeouts in 58 2/3 innings with Triple-A Memphis in 2008. He has 84 Minor League saves since being selected by the Cards in the 12th round of the 2004 First-Year Player Draft out of Florida International University.
Towers said there's upside with the player to be named later, going as far to say that "the player to be named later would be as good if not better than Worrell."
The Padres have until April 1 to choose from three players, two pitchers and a position player.
"There's a couple guys we want to look at in Spring Training," Towers said, noting that one of the three players could already be frozen on the Cardinals' 40-man roster.
Towers has said often this offseason that he wanted to add Major League-ready pitching -- either starters or relievers -- in return for any deal that may be made.
"We've been trying to add depth to our pitching staff and feel like we have with Mark Worrell," Towers said.
That could still happen, as Towers hopes to deal pitcher Jake Peavy and his $11 million contract sooner rather than later. In fact, Peavy trade talk has occupied much of Towers' offseason.
The talks regarding Greene weren't nearly as frequent, and the deal happened relatively fast. It wasn't until Wednesday when a report in the New York Post said Greene was on the verge of being moved.
"I would say it happened with St. Louis in the last 24 hours," Towers said. "We kind of liked the package St. Louis had to offer. They expressed some interest at the GM meetings. [St. Louis GM John Mozeliak] Mo gave me a call yesterday afternoon and names were exchanged in a three-, four-hour period."
Greene, the Padres' first-round pick in 2002 out of Clemson, broke into the Major Leagues in 2003 and became the full-time starter the following season. He excelled defensively and showed good power for a middle infielder during his time in San Diego.
Greene's time with the Padres was marred by injuries -- he played in 140 or more games once in his five seasons in San Diego. His best season came in 2007, when he remained healthy and played in 153 games.
"I would like to thank the San Diego Padres, the city and fans of San Diego for the opportunity to play in San Diego for five-plus seasons," Greene said in a statement. "The fans of San Diego will be missed and I appreciate their support through not only the great times but also through the down times. I can't wait until April gets here."
Greene, who was named the team MVP in 2007, reached career highs in home runs (27) and RBIs (97) while hitting .254 for a team that missed the postseason by one game.
But Greene couldn't replicate that success in 2008, struggling from the start of the season. He hit .214 in April and .196 in May. Finally, on July 30, Greene's frustrations got the best of him when he struck a storage unit outside the dugout after his 100th strikeout of the season, breaking a bone in his left hand.
Greene missed the final two months of the season with the injury, and the team filed a grievance to recover as much as $1.47 million of Greene's 2008 salary ($4.5 million) because of the nature of the injury.
Greene, 29, was replaced at shortstop by Luis Rodriguez, a natural second baseman, who hit .315 in August and .304 in September.
"We're certainly losing a guy who has been a valuable shortstop to us," Towers said. "A major contributor to division-championship ballclubs, gave us all memorable moments on the field. I think it's always tough when you move guys who are homegrown."
Towers indicated that the Padres made Greene a multiyear offer "over 12 months ago," but he felt it was doubtful that Greene would stay after his current contract expired. Reports had that offer at four years and $29 million.
Unless the team make another deal to land a true shortstop, Rodriguez will likely be the odds-on favorite to start there in 2009, though Towers wouldn't rule out adding a shortstop through free agency or trade.
"It's never easy," Towers said of finding Major League-caliber shortstops. "I would say our best option is via trade. There's some people we've kind of identified as free-agency as well as some trade opportunities that may exist."
Towers said that while moving Greene and his salary help a team looking to reduce payroll for 2009, he said that wasn't the only factor involved.
"We're certainly reducing our payroll. ... I'm not going to say that didn't play into it," Towers said. "Salary and it was a guy we weren't going to be able to retain."