PROVIDENCE, R.I. — Since Sean Miller arrived at Arizona in 2009, every spring has been something of a mad scramble.

The first two springs were about roster building, trying to replenish a talent level drained by years of uncertain coaching transition.

Soon after, it was about replacing transfers and other departees with recruits who fit better, a process that led into 2012 after Josiah Turner and Sidiki Johnson took off after troubled freshman seasons.

Since then, it’s largely been about replacing high-level talent that leaves early every spring for pro ball, six guys in the past three springs.

But Arizona has more of an old-fashioned kind of problem this spring: Four seniors are gone and, combined with other potential issues, could make it the most critical spring yet for Miller’s recruiting.

In all, Arizona could lose half of its 12 scholarship players from this season.

Gabe York, Kaleb Tarczewski, Ryan Anderson and Mark Tollefsen are seniors, Elliott Pitts’ future at UA appears doubtful because of an off-court issue that prompted him to leave the team in February. And Allonzo Trier could at least test the NBA draft waters, a process which is now allowed again until May.

If all those guys took off, that would leave Arizona with a collective seven years of college playing experience among six returnees (including Ray Smith, who is a returner but gained no playing experience as a freshman while sitting out with a torn ACL).

So bodies are needed. Talented bodies who can play right away.

“It’s an important recruiting class,” Miller said. “I think for us to be able to hit it out of the park in the next month is big. Hopefully we can do that.”

Miller is on his way already.

The Wildcats have three five-star talents on board, with Finnish forward Lauri Markkanen having signed a letter of intent last November while guards Kobi Simmons and Rawle Alkins have since made non-binding commitments and are expected to sign during the spring period that begins next month.

Here’s a look at five key questions as Arizona enters the spring transition season:

1. Who else is coming in?

Miller has said he wants to add four or five signees to Markkanen for the 2016 class, which means at least two more this spring. There’s little doubt that his first choice would be forward Josh Jackson, the composite No. 1 player in the class of 2016 (according to 247 Sports; ESPN has him at No. 3) and a player on Miller’s 2015 USA Basketball U19 team last summer.

A Detroit-area product now playing out of Napa, California, Jackson is considering Michigan State, Arizona and Kansas and has said he might decide by the end of this month.

Another of the USA Basketball U19 players last summer, Dallas guard Terrance Ferguson, is also considering UA after decommitting from Alabama on March 1.

Miller has also shown a penchant for picking up transfers in the spring, both traditional (T.J. McConnell and Ryan Anderson) and the immediately eligible grad transfer (Mark Lyons and Mark Tollefsen).

2. Does Trier test the waters (and stay in them?)

The NCAA has shifted back toward allowing players to go through the NBA predraft process and not lose any remaining eligibility until a week after the NBA combine in May.

That means it’s an easy decision for any legitimate prospect to at least gauge their market value in pro ball, unless they are overwhelmingly set on returning to school.

Trier said Thursday he couldn’t address whether he would at least test the draft, since it was too early after UA’s final game.

But at 20, he’s only four months younger than former UA forward Aaron Gordon, who is in his second year in the NBA.

Yet he still might have plenty of upside. Draft Express president Jonathan Givony, who attended UA’s NCAA Tournament game, said Trier can raise his stock by improving in a number of areas, including defensively, if he returns for a strong sophomore season.

Currently, Draft Express predicts Trier going No. 35 in the 2017 NBA draft and No. 61 on its overall list of the top 100 prospects.

3. Will Pitts return?

Miller says he’d like to say more about Pitts and will be able to someday. But that day hasn’t come yet.

So all that’s certain now is that Pitts hasn’t played since Dec. 5, left the team in mid-February for good and is still attending classes at UA. That doesn’t exactly bode well for a return, maybe just an effort to keep him eligible so he can go somewhere else.

But as a junior, Pitts is also in a restricted position. If he transfers, he’ll have to sit out the required year in residence before playing somewhere else — and since he is still enrolled at UA, that means he can’t play until November 2017 elsewhere, nearly two years after he stopped playing for the Wildcats.

The exceptions would be if Pitts received a waiver because of his issue, or if he transferred down to Division II. Then he could play right away.

But he would also have only one more year to play unless he receives a waiver, since players can’t receive a redshirt year for non-medical reasons once they have played in a regular-season game. Pitts played two full seasons and seven games this season.

4. Is anybody else taking off?

It’s never a certainty at Arizona, or anywhere in high-major basketball, really, that anyone with eligibility returns.

But Kadeem Allen, Parker Jackson-Cartwright, Dusan Ristic and Chance Comanche all played the kind of roles and spoke the kind of words that suggest they’re locked in to come back.

Justin Simon, who only played in 24 of UA’s 34 games, told the Star earlier this month that he’s “loved every second I’ve been at Arizona,” while Smith quickly quashed speculation that he might go elsewhere.

“For all of those asking will I play in a Arizona uniform YES !!! #IAINTGOINNOWHERE” he posted on Twitter.

A departure by Smith would be appear illogical anyway, since he’s coming off two straight years of ACL tears. He would have had to transfer and sit out a year in residence somewhere else — making it three in a row that he’s been off the floor — or hope that a pro team takes a flier on his considerable potential.

5. Can the returnees get better?

Ristic, Comanche and Simon all appeared to grow when given the chance for more playing time this season.

While Tarczewski missed eight games with a foot injury, Ristic averaged 9.2 points and 4.6 rebounds, and shot 60.9 percent from the field.

Meanwhile, Comanche pretty much forced himself into the rotation at the tail end of the season, showing considerable upside on his 6-10 frame.

But all three also spent a lot of time on the bench, especially Simon, and Ristic finished the season particularly less effective than he was when Tarczewski was out.

Ristic wound up averaging 7.1 points, 3.8 rebounds and 55 percent shooting.

“I think I did a good job for the first couple of games when Kaleb was absent,” Ristic said. “I just didn’t think I did a good job at the end of the season. For some reason my confidence went down. I don’t know why.

“What I can do is just work hard in the offseason and great ready for the next season.”

Same goes for everyone else that will return. Trier said “the guys who come back next year will be prepared, so we don’t have this feeling again.”

Clearly, Ristic is one of those guys.

“I want to do something with all this,” Ristic said. “We lost in the first round. I don’t want to be in the same position next year. This gives us motivation for next year.”

Sportswriter for the Arizona Daily Star covering Arizona Wildcats basketball