Four years ago the Leafs rushed an 18-year-old Luke Schenn to the NHL, and it looks like the team is prepared to do the same with Morgan Rielly.“I’m gonna pick the best players,” Randy Carlyle told the Toronto Star . “If (Rielly) is among the best, I’ll have no qualms picking him because he’s 18.”Management has echoed the coach's philosophy.“If Morgan Rielly can help our team win, I really don’t care that he’s only 18,” Dave Nonis told the National Post . "If he’s ready, he’ll stick around."The hope would be that Rielly could help upgrade the Leafs' blueline, one which has been near the bottom of the league for years. He is a slick-skating, puck-moving defenceman that could potentially step in and provide a reasonable facsimile of Jake Gardiner, who is currently out with a concussion.The Leafs can give Rielly a five-game try-out (a sixth game automatically burns a year on his contract), but allowing him to make the Leafs this season, regardless of how NHL-ready he may appear, would be a monumental failure.An entry-level contract is one of the most valuable assets in the NHL. Having a cap hit so low, with the potential to provide production that greatly exceeds the cost for three years, gives tremendous flexibility to maximize talent on the rest of the roster. To waste a full year of an entry-level contract on a lockout-shortened season, one in which the Leafs are already well situated under the cap, is short-sighted and misguided.Having Rielly on the team this year fails to maximize his ELC. Normally, if a player doesn't spend any time in the AHL, he can play 246 regular season games on an ELC. With Rielly, however, the maximum amount of games the Leafs could get out of his deal is only 212. If Rielly is a truly special player, why flush away an extra 40+ games of cheap production? It makes no sense.Compounding the imprudence of wasting a year of an ELC on a shortened season is Rielly's age. Rielly will not turn 19 until March. In the history of the NHL, only 27 defenceman played more than 10 games in the NHL during their 18-year-old season (meaning they were 18 on February 1; players like Cam Fowler andwere rookies in their 19-year-old season).To make matters worse, Rielly is vastly different than most of those precocious defencemen: He missed almost all of his draft year with a torn ACL ( which, despite advances in medicine, is still a very serious injury) The only player to play as few games as Rielly did during his draft year and then play in the NHL as an 18-year-old was, who played in 18 Czech league games and another 12 internationally in 1983-84.It is not only rare to have a player as young as Rielly make the NHL, but it is almost unprecedented to have one who played in so few games during his draft year. This concern is somewhat mitigated by the NHL's late start to the season, which has provided Rielly with an extra 65 games of junior hockey (plus those in the World Junior Hockey Championship), giving him 127 career WHL games. But that means Rielly has just now, one year after being drafted, accumulated the same amount of experience as most draftees had back in June.Rielly has had a nice junior season so far; he was second on the Moose Jaw Warriors in points (28) before leaving to play in the World Junior Hockey Championship, and he has also played in the Subway Super Series. But he hasn't been so utterly dominant that a smooth transition to the NHL is assured. In fact, even though he was selected to Team Canada's world junior roster, he didn't play a large role on the team (something not totally shocking considering he was an 18-year-old among mostly 19-year-olds on the blueline). If he was truly knocking on the NHL's door, he would have played a greater role on the team.Besides, he isn't at a level in which going back to junior is detrimental. There is still plenty Rielly can learn in Moose Jaw, away from the glaring lights of Toronto where every tiny mistake will be magnified and discussed ad nauseum. Like many young defenceman, he could still use work in his own defensive zone and could benefit from playing major minutes in all situations, which he would be unlikely to do in the NHL. He's also a leader for Moose Jaw, so spending more time in junior can help develop a skill that has been severely lacking on the Maple Leafs since Mats Sundin departed.Another factor working against Rielly, a left-handed shot, is Toronto's defensive depth. There are five left-handed shots ahead of Rielly on the roster: Dion Phaneuf, Carl Gunnarsson, Jake Gardiner, John-Michael Liles, and Paul Ranger (although he is only signed to an AHL deal). The right-handed shots are much weaker: Cody Franson, Mike Komisarek, Korbinian Holzer, and Mike Kostka. For Moose Jaw, Rielly has played on both the left and right side, so unless Carlyle moved a veteran to their off-wing, his most likely shot at making the team would be on the right side. But putting him in a position to enter the NHL with as little experience as he has, on his off-wing, isn't putting him in an ideal situation to succeed. And for a rebuilding team like Toronto, doing anything that can negatively affect the development of a blue chip prospect for a short-term boost is foolish.For Leafs fans, the desire to see Rielly make the team is based on excitement. It's no fun waiting around for prospects develop. The Leafs spent a high draft pick on him and fans want to see how he'll do in the NHL now. As Michael Langlois says , "It’s been a while since we have been this excited about a draft pick. As a result, we can’t wait to unwrap the new present."But remember, not too long ago Luke Schenn was an exciting 18-year-old rookie, and now, four years later, he's off the team after what was an astonishingly abysmal season. The new shine fades quickly on rushed prospects.For the Leafs, the pressure to see Rielly in action now shouldn't even be a factor. Management should be thinking about what's best for Rielly, and consequently the team, long-term. Rielly may help the team now, but in all likelihood, unless he's some sort of transcendental player (which he has not made apparent), he will help the team more in the future if he goes back to junior now.For the record, during the pre-season last year I was against Jake Gardiner making the Leafs and look how well that turned out. That said, Gardiner was in a much different position than Rielly. He was older and had already completed three years of college hockey, which is comprised of much more physically mature players than in junior. Gardiner didn't take as direct a route to the NHL that Rielly would be taking. Plus, Gardiner wasn't injured for almost all of the previous year.Every rational argument points to keeping Rielly in junior at this age. If Carlyle wants to keep Rielly after training camp Nonis needs to step in and take the option away from him, sending the talented rearguard back to junior where he belongs. It might not do him any favours with his coach, but it is the best thing for the team long-term.