The answer could be as simple as this: They like Erik Bedard better.
Bedard, 32, was signed to a similar contract, one year and $4.5 million, shortly after the Pirates bought out Maholm's $9.75 million club option for 2012 early in December.
Management was impressed with his 3.62 ERA in 24 starts split between Seattle and Boston last year, feeling he is one of baseball's most effective left-handers when healthy.
That health factor usually is a big if with Bedard. He missed 2010 because of a shoulder injury, that part of a long list. But he is supposed to be fully healthy entering spring training.
Bedard also sounded genuinely upbeat about joining the Pirates for what will be his first National League experience after eight seasons in the American League.
"They're a really good, young team, a team that's made a lot of strides," Bedard said. "I'm just looking to come over and add some pitching depth and help them win.
"When you have a lot of young talent, it makes for a lot of excitement. I'm a little older, but I'm looking forward to being part of that."
Bedard will be the only left-hander in a rotation that also consists of Jeff Karstens, James McDonald, Charlie Morton and Kevin Correia.
--CF Andrew McCutchen, the Pirates' best player, is not on the trading block, but general manager Neal Huntington raised eyebrows this week when he told MLB Network Radio: "Never say never. If someone wants to back up the truck and give us one of those organization-altering deals, it's something we'd have to listen to. It would have to be a dramatic overpay on the part of the other club."
--The Pirates signed RHP Daniel Cabrera to a minor league contract in hopes that he can resuscitate his career at age 30 despite not pitching in the majors since 2009. Cabrera throws hard, but his average of 5.2 walks per nine innings contributed greatly to his 5.10 career ERA. He's be in the mix for bullpen depth.
--1B Derrek Lee remains available in free agency, though the Pirates are not optimistic about his return. Lee already turned down the team's offer of salary arbitration, which essentially would have guaranteed him $7.25 million, his price last year, and he is known to be considering retirement if he doesn't get one of the small handful of options he'd prefer.
--C Rod Barajas will enter camp as the team's starter behind the plate, but management will open the competition for backup between Michael McKenry and Jose Morales, the latter having been recently signed to a minor league deal.
--OF Josh Bell, the Pirates' $5 million second-round draft pick last summer, will make his professional debut with low Class A West Virginia. That's usually where the Pirates put elite talent coming out of high school. "Josh's primary focus will be on adjusting to the daily grinds of professional baseball and understanding our expectations," said Kyle Stark, the Pirates' director of player development.
BY THE NUMBERS: 4 -- Prospects the Pirates placed onto MLB.com's annual top 100 list: RHP Jameson Taillon (No. 8), RHP Gerrit Cole (No. 11), CF Starling Marte (No. 40) and OF Josh Bell (No. 69).
QUOTE TO NOTE: "Last year was all about belief, incorporating belief in them, individually and as a group. Now the thing we'll talk about is the ability to finish and sustain success throughout the season." -- Manager Clint Hurdle.