The move has surprised many, with Vancouverite Yallop expected to be a shoe-in for the Caps coaching job, ticking all the boxes that club's now infamous committee are looking for, in particular experience, success in MLS and a history of bringing on young players.
You have to feel that the lure of an actual job offer was far better than playing the waiting game for what was a dream job in his hometown. We can only speculate as to whether Yallop expected to be installed by the Whitecaps right away and didn't want the uncertainty when it became clear he wasn't going to be without a full interview process.
There's also that lingering talk that the whole "committee" aspect of the Whitecaps was putting off Yallop and the move to Chicago, who had already spoken to him about becoming the technical director at the club, would give him more freedom to make all the decisions and have complete overall control.
In Monday's article where we broke the news of Rennie's release, we asked the question of Yallop - "was his 2012 Quakes a blip and he is a manager whose best days are behind him and he is coming to the team with outdated ideas that won't be a success here?".
We'll find out next season with Chicago, but losing Yallop to the Fire may actually be a blessing in disguise, depending on who ends up applying for the job, and the Whitecaps should end up with a more modern and dynamic new coach.
The Caps had confirmed that Yallop was someone that would be on their shortlist, but it now throws up the intriguing question as to who is on that list now and who will ultimately get the job?
There's already a lot of sites out there listing and analysing candidates, so we're not going to bore everyone by overdoing that. Some names are available right this second (Bob Bradley, Gary Smith), whilst others are still in jobs (Bruce Arena, Dominic Kinnear, Jason Kreis).
Tuesday's press conference was keen to play the "experience" card. Bobby Lenarduzzi, Jay DeMerit and Jordan Harvey all talked about the need for experience and you left feeling that the new manager would be more of a veteran than an up and coming young buck.
Now that the dust has settled, and having given it a bit of thought after losing out on Yallop, I'm not sure that would necessarily be the best or only route to go down right now.
For me personally, I would narrow it down to two candidates, either of whom I would be happy to see as the new Caps head honcho.
My first choice is Jason Kreis. We first mentioned him as a bit of a pipe dream in a podcast back in May when we were sure Rennie was getting fired back then.
The RSL boss has a lot of invaluable MLS experience and success behind him. He is only 40 but has been in charge in Utah since 2007.
Whilst it is felt that he is currently at the stage of his career where he will be tempted by a new challenge, the downside is that he has been strongly linked with being the inaugural manager at New York City for 2015. But that is a whole season away. Would a manager like him be happy to not have a hands on, active role for a whole year?
I love what he's done at Salt Lake, especially this year, where he lost key players, rebuilt his team, again, and whilst many thought he would struggle, he proved his doubters wrong and came close to winning the Supporters' Shield.
He also has a track record for developing young talent, which is right up there along with results as to why the Caps brass felt that Rennie had failed.
I think the Caps would love to have a guy like Kreis at the club and are bound to put feelers out to him, which I'm sure they already have.
He couldn't come until RSL were out of the playoffs, which could be as late as December, not giving him a whole lot of time to make decisions on which players are kept and which ones are binned and would hopefully rely on someone already at the club adequately informed to help him make those decisions.
And that person would be Carl Robinson, who is now my second choice for the job if we can't lure Kreis.
This might surprise some because we were on the experienced manager bandwagon for the last few weeks.
When we first got wind that Rennie was going, I didn't think Robinson was the right man for the job at this specific time, mainly down to him not having managerial experience as the leading man so to speak and we can't afford another project that doesn't work out.
I could easily have seen Yallop grooming him for that position down the line before moving upstairs, but you know what, why not give him a shot?
He's a great coach, respected and cited by players and I know for a fact that he is highly thought of by some of the Caps top brass.
Talk with him and within minutes you know that he knows the game inside and out and has a passion to succeed.
The huge advantage with Robinson is that he knows the squad. If the general feeling is that we fell just short, he'll know exactly what and who is needed to take us to that extra level and who needs to go now to achieve it. But could he get the necessary results and would he be given the necessary time if things started off badly?
What I like about Robinson, and Paul Ritchie for that matter, is that they tell it like it is. There's no spin, just refreshing honesty. And do you know who else likes that? The players.
Both are highly respected by the current squad, including the veteran players who know they've played at a high level and worked hard to get their coaching qualifications.
If Robinson got the coach's job, I'd expect Ritchie to stay around as his assistant and would be delighted by that young and ambitious pairing and I think they would bring success if they are allowed to make the moves that are needed, which for me is still to clear out a lot of the deadwood and bring in up to 10 new players.
You can be certain they'd play exciting and entertaining football both home and away, and from speaking with both of them in the past, they are very big on developing younger players and feel that bringing through young Canadian talent from the Residency is the only future for the Caps.
But does Robinson stand a realistic chance or have the club painted themselves into a corner with the experience comments? How would promoting the assistant to a perceived failed manager look to the general fanbase? Are the owners bold enough to take the gamble with another young manager, and a rookie one at that? Or do they have to go out and get a "name" to appease and stop disillusionment?
It's going to be an interesting couple of weeks, but as we keep saying, this next appointment is one of the most important in Whitecaps history and will define the future of this football club.
It's added pressure, but with Yallop's Chicago appointment, they perhaps now have more time and are less rushed to make sure they get the right man in place.
The powers that be can't afford to get it wrong.
If they went for Kreis, Robinson or both, then I don't think they would be.