In a way, the new early signing period was always a litmus test: How would it impact a school such as Arizona, which had been the victim of last-minute poaching in recent years?

The early signing period — which began Wednesday and runs through Friday — would, in theory, work like an effective running game. It would shorten the clock.

The early results were mostly positive for the Wildcats. They signed just about everyone they were planning to sign on Day 1 — including a player who had drawn the interest of one of their conference rivals.

Arizona announced the addition of 16 players Wednesday. The last to sign was cornerback McKenzie Barnes of Edison High in Fresno, California.

On Tuesday, Barnes revealed that he had received an offer from UCLA. “Aww, man,” he tweeted. “This is BIG.”

With Chip Kelly now coaching the Bruins, UA fans understandably were worried. With Barnes waiting until almost 5 p.m. Tucson time to make his college choice official, their anxiety only grew.

They breathed a collective sigh of relief when Barnes stuck to his pledge and signed with Arizona. In addition to his signature, he delivered two all-caps tweets soon after. One read: “SIGNED, SEALED, DELIVERED. I’M YOURS. #beardown.” The other read: “DREAMS COME TRUE!!”

Barnes clearly felt he made the right decision. He told that the opportunity to play right away sold him on Arizona — yet another way in which the Wildcats’ prolific 2017 class is paying immediate dividends.

Barnes wasn’t the only Arizona commit to receive a late UCLA offer, and the other would-be Wildcat didn’t sign Wednesday. Tailback Martell Irby of San Diego Morse High School remains on the market.

Irby didn’t sign with UCLA either. He could make his decision sometime in the next two days or wait until Feb. 7. Of the known commits who didn’t sign with Arizona on Wednesday, he’s the only who might before the early period ends.

UA coach Rich Rodriguez had predicted that 70 percent of recruits would sign early, and he was pretty spot-on. Fifteen of Arizona’s 21 verbal commits signed. The latter figure includes Las Vegas receiver Jaden Mitchell, who is delaying his enrollment after hurting his knee this past season. The 16th newcomer is defensive tackle PJ Johnson of City College of San Francisco, who committed to and signed with Arizona on Wednesday.

Two of the top players in the Wildcats’ class — quarterback Jamarye Joiner of Cienega and defensive end Adam Plant Jr. of Las Vegas —weren’t expected to sign and didn’t. Both told the Star in recent days that they are “100 percent” committed to Arizona but prefer to wait until February to make it official.

Amphi offensive lineman David Watson had no such reservations. Watson sent in his letter of intent early Wednesday morning. Arizona announced his arrival at 8:10 a.m.

The son of former UA softball star Lauren Espinoza-Watson and ex-UA lineman David Watson wasn’t planning to hold an elaborate celebration. But after thinking about all the people who helped him reach that point, the younger David Watson wanted a forum to thank them.

About 50 of Watson’s family members, friends, coaches and teachers gathered inside Panther Hall at Amphi on Wednesday evening. They were treated to red-, white- and blue-frosted cupcakes. Watson stood behind a dais adorned with red balloons, UA paraphernalia, a poster of him in his Amphi uniform and a framed picture with a block A as the backdrop.

“Leading up to today, my parents asked me if I wanted a party or get-together to celebrate the signing of my letter of intent,” Watson said. “At first I told them no. But as I thought about it, I realized I needed this. … I needed it so I could recognize the people that helped me along the way.

“When people ask me what it takes to play at the next level, I can tell them this: Look around the room. This is what it took for me to get here.”

Watson was one of three offensive linemen to sign with Arizona on Wednesday. The Wildcats also added three defensive linemen. Johnson and fellow defensive tackle Mykee Irving of Calabasas, California, are listed at over 300 pounds. Securing their services accomplished one of the UA coaching staff’s primary goals.

“Our biggest need was to get bigger and stronger in the trenches on both sides of the ball,” Rodriguez said. “We’re excited about the linemen we’re bringing in, and we’ll continue to make these positions a priority as we complete this class and others in the coming seasons.”

Fourteen of Arizona’s 16 signees are listed at 6-2 or taller.