I'm not so sure this narrative around trading him now will maximize his return than at the deadline exists anymore. With the expanded playoffs and the way the playoffs function (the bye round hasn't really helped teams that much), MLB has basically turned into the NHL and NBA where the first four months of the season don't matter.
Back in the day when you had to win your division to see a playoff spot, the 3 extra WAR by having Guerrero on your team from April to July really helps. Now, not so much. It's a trade-off now. Guerrero has less team control by July, but each team has more information, including the Jays. The former obviously decreases his value. The latter increases his value to some teams, potentially more than the former decreases it and his value goes up.
The biggest risk you have is if he falls off a cliff and tanks his value in July. But if that happens, there will be a limited bidding war for him during free agency and you might be able to sign him at a reasonable price.
The second biggest "risk" is that he performs extremely well. So well that the Jays are contenders and won't trade him at all.