Thanks to emilylovesthedbacks for spotting this on twitter, more info to come.
[Updated] The deal sees the Cubs getting a pair of prospects, in left-handed reliever Scott Maine and infielder Ryne White. Said Josh Byrnes, "Aaron has been a successful, durable reliever who will add experience and stability to our bullpen." The right-hander is 31, and had a 4.11 ERA in 72.1 innings for the Cubs in 2009.
(Update) Credit also goes to Counsellmember, who also mentioned this in the Lincecum Cy Young post.
Maine, 24, was the D-backs sixth-round selection in the 2007 First-Year Player Draft. In 2009, he went a combined 4-5 with 7 saves and a 2.90 ERA (20 ER in 62.0 IP) in 48 relief appearances at Double-A Mobile and Triple-A Reno. Over parts of three seasons in the D-backs farm system, he went 8-7 with 13 saves and a 3.29 ERA (44 ER in 120.1 IP) in 88 relief outings. White, 23, was the D-backs fourth-round selection in the 2008 First-Year Player Draft. In 2009, he hit .266 (111-for-418) with 18 doubles, 1 triple, 6 home runs and 52 RBI in 116 games for Single-A Visalia. Over parts of two season in Arizona’s minor league system, he hit .275 (194-for-705) with 37 doubles, 2 triples, 13 home runs and 103 RBI in 186 games.
Interestingly, the official press release is careful to mention Heilman's stats as a starter, even though he hasn't been one for the past four seasons. His agent told the New York Daily News in November last year: "The object the entire time has never been to get out of New York. The object is to get out of the bullpen. The most success he's ever had as a pitcher has been as a starting pitcher. He was drafted by the Mets as a starting pitcher." That didn't happen after his trade to Chicago, and one wonders if it's something the team might try here? He earned $1.625m in 2009, so would be a cheap enough member of the rotation if so. Of course, the question of whether he can be a starter is a huge one.
But even if not, he should be an innings-eater in the bullpen. Among "pure" relievers, no-one has pitched more innings over the past four seasonss than Heilman. Interestingly, second on the list is another name we might recognize, Jon Rauch, who was born less than two months before Heilman in 1979. One thing I note is that Heilman's ERA+ over that time (109) doesn't quite seem to mesh with his opponent's OPS: he has held hitters to a decent line of .241/.322/.378. If you look at the other relievers in the chart linked above, that kind of OPS tends to result in better ERA numbers.
xFIP has Heilman at 4.15 last year, which is pretty close to his actual ERA. His groundball numbers are a little worrying, being below MLB average for the past two seasons, and heading the wrong way too, though this is mitigated by decent infield-fly rates. His K:BB ratio have not been brilliant either, at about 1.8, which is mediocre in the true sense [league average last year for relievers was 1.87]. Overall, I feel somewhat "meh" about the deal: I tend to feel it gives the bullpen more depth, without really improving the quality enormously. However, about a quarter of his appearances involved him going more than one inning, and about 30% were on zero days rest, so he may help relieve our relievers, at it were.