The Leafs may not have a GM, but that doesn't seem to be stopping trades from going through.
According to Andy Strickland, the Leafs have acquired forward Zach Hyman's rights from the Panthers in exchange for Marlies center Greg McKegg. The Leafs have also acquired a conditional 7th round pick, which is the NHL trade version of ¯\_(ツ)_/¯.
If I had to guess, the condition would probably be signing Hyman.
The deal was then confirmed by the Leafs:
Toronto Maple Leafs (@MapleLeafs) June 19, 2015
Hyman was drafted in the 5th round of the 2010 entry draft, but never signed a deal with Florida (who drafted him). He most recently has played in the NCAA for the University of Michigan, where he recorded 54 points in 37 games this past season, leading the Wolverines.
McKegg was drafted in the early third round of the 2010 entry draft, but aside from getting a cup of coffee with the Leafs, never did much at the NHL level. He was a valuable contributor for the Marlies, however, posting 47 points in 65 games in 2013/2014, and 37 points in 62 games in 2014/2015. This trade presumably leaves a hole on the Marlies for a top 6 center (under the assumption Hyman will be with the big club), which may be filled by William Nylander shifting over from the wing.
On it's face, this seems like a very 'meh' trade, but it's a little perplexing. The Leafs will have to sign Hyman (who will be a UFA this summer), and it's not like he has much of a background of success. Aside from his last season in the NCAA, he wasn't really a player of note. And a lot of his success last year might be explained by the fact that he played with Dylan Larkin. According to this article from TheLeafsNation, his Prospect Cohort Success % is only 15 (essentially, only 15% of comparable players had a NHL career of > 200 games). We'll have to wait and see about this trade, I suppose, but at first blush, I'm a little confused by it.