Reaves doesn't do much else besides provide energy on the ice and fight, so the team cannot really count on him to score an important goal when they need it. It doesn't help that Reaves only plays five or so minutes a night. He doesn't get much ice time because teams have higher chances of scoring goals when he's on the ice. Reaves also takes a ton of penalties, which means the Leafs are always having to be on the penalty kill.
Reaves is getting paid $1.35 million per year, however for what he brings, spending that much money is simply too much for the Leafs. Reaves only had six points in 49 games last season, and had a awful -13 rating. The Leafs need to improve their bottom six forward group, and Reaves definitely isn't the solution. The Leafs should try to trade him and get a player that they can pay the league minimum salary who will score more than Reaves. All they need is someone who can score 10 goals, and that would already be an upgrade.
Fans are concerned that it will be hard to trade Reaves, however there are teams out there who would like a player like him, but it's clearly not the Leafs. There are teams who would be willing to take on his salary, and the Leafs likely wouldn't have to give up any top prospects for other clubs to acquire Reaves. GM Brad Treliving could possibly attach a mid or late round draft pick and that would make the deal official likely.
PuckPedia claims The Leafs have about $1.275M remaining in salary cap space. If they are able to actually move Reaves, they would then be at $2.625M in available space. If Kampf or Jarnkrok, as mentioned above, are also traded, that would put their available salary cap space to about $4.8 million or so, which they could then use to sign a good player than can score 20 to 25 goals or possibly add a solid defenceman. The Leafs have a lot of options to make their team better, and clearly Brad Treliving will need to get things going by trading away Ryan Reaves.