Hi BigRuss (and chels),
believe it or not, this is one of the tougher questions I have ever been asked here!
Without a full list of stats and heat maps, it's really hard to determine what happened with McLean, but here are things we do know:
You are spot on about the timing coinciding with the Lin Jong injury.
The Bulldogs play a Hawthorn type model Midfield, where so many players rotate through, it's going to be hard to pick any of them as good SC Mids (I'm looking at you, Bont!). Hawthorn at it's peak rarely produced good SC Mids. Fortunately, you are not stuck with McLean as Mid only, but it should give an indication, that any permanent type improvement he shows might be capped by this factor.
Normally we can try and find something in the stats we do have access to, to show a player has shifted from a Def or Fwd role, to more Mid time. McLean has nearly all of those indicators. Probably enough to say it happened, without having access to his heat maps. In the case of a small Forward going to the Midfield, you are looking for:
An increase in Inside 50's, as he spending more time outside the arc. Rnds 1-13 3.1/game. Rnds 14-23 4.1/game (
check)
An increase in Rebound 50's, as he's pushing deeper now. Rnds 1-13 0.6/game. Rnds 14-23 1.0/game (
check)
An increase in Clearances, as he attends more stoppages. Rnds 1-13 1.8/game. Rnds 14-23 4.1/game (
CHECK)
An increase in Contested Possession rate. Rnds 1-13 33.7%. Rnds 14-23 43.7% (
check)
There are a few other smaller ones, but they are the main ones, so it looks like there was no doubt he played significantly more Mid time after Round 13, when Jong got injured. Even with that, I wouldn't be confidently predicting he can reach Forward Keeper status. From what I understand, Jong will be back very early in the season, maybe even round 1. If that even takes away half of McLean's Mid time, he might be mired in that awkward low 90's area. It's a very grey area. None of the Bulldogs retirement/delistings open the door for Midtime, with Boyd, Murphy and Stringer all playing some Mid Time, but not enough to open a door for McLean to get significantly more.
You probably won't lose too much value on him, if it goes wrong, and there is potential for upside, I just think I'd want a more positive lead to be taking a player at his price, and his history, especially in a team with the Midfield model the Bulldogs (and now many other teams) use. His fall back role is that poisonous small Forward role!
As to which Forwards I like in that $400-$480k area, I only have 2 right now, and only one I'm looking at as a long term pick. It might be silly using the words "long term" with Barlow, but he has never been out of my team since news of his fitness levels being back (the other is Lynch, with the expectation of trading him at or before his bye).
Good luck, I hope you jump the right way.