More likely, he saw the calendar for collecting nominating signatures getting short (due at the end of the month) and he would be trying to raise money in a field that already has three experienced Republicans running.
On top of all that, it's simply just easier to get on the ballot as a legislative candidate than as a Congressional candidate (compare the signature requirements for LD1 with the requirements for CD4)
...Rumors have been swirling about the possible Congressional candidacy of Lisa Borowsky, a Republican and a member of the Scottsdale City Council. She has put those particular rumors to rest by announcing that she will be running in the new CD9.
Not a total surprise. Her council seat is up for reelection this year and she hasn't formed a reelection committee yet, and the timing on that is the same as the timing on a run for Congress.
However, unlike the Rs in CD4, the Rs in CD9 aren't as experienced, half never having held elected office and the other half never having held office higher than city/town council. And none of them seem to be pulling away in the race.
Combine that with the fact that she would need more signatures to get on Scottsdale's ballot (1000) than to get on the CD9 primary ballot (616)
Taking a shot at the rare truly open Congressional seat isn't a difficult decision under the circumstances.
...There may be more people to jump into Congressional races, but at this point, look for those people to be well-funded enough to hire signature gatherers at premium, "last minute" rates, or to be simply crazy.
In other words, I believe the fields in the various CDs are pretty much set; it's just a matter of seeing which candidates actually qualify for the ballot.