The earliest indicator of a potential trade is seeing who is scouting who at hockey games. It often doesn't amount to anything in the end, as the process of planning and executing a trade can be very tricky, but when there are multiple appearances of a team's scouting staff watching the same team in a concentrated time frame, the likelihood of something happening increases significantly.
And then if the other team is spotted scouting them as well, you unofficially have dance partners.
Such is the case with the Pittsburgh Penguins and Los Angeles Kings. The Kings have watched the last 4 games in Pittsburgh, while the Penguins were spotted at the most recent Kings' game.
Ian Cole is obviously the number one player on the Penguins' trading block, while Conor Sheary is another player Jim Rutherford would ideally like to move if possible. His inconsistency and relatively high salary will be hard to move, however.
On the Kings' side, perhaps Mike Amadio or Paul LaDue are of interest to Pittsburgh. A centre and a D, both could interest Rutherford, but neither ultimately fulfills his need for a top 3 centreman. But something tells us a trade for Cole or Sheary probably won't yield that highly coveted piece he's been searching for all season.
A trade between the two teams will likely be a package of a prospect and a pick for a roster player.
Ask anyone in the hockey media and they'll tell you with out a shadow of a doubt, Rutherford will make at least one trade, if not more, before the trade deadline hits. It's just a matter of when, and with whom.