CHICAGO -- If there were any doubts that Nelson Velazquez should be rostered for next season, the Cubs prospect let his bat plead his case for him throughout a torrid Arizona Fall League performance.

Prior to Friday's 5 p.m. CT deadline for 40-man roster additions -- which protects eligible players from the annual Rule 5 Draft process -- Velazquez received some well-earned good news. The outfield prospect was one of two players, along with righty Ethan Roberts, whose contracts were selected by the North Siders.

"My goal here is to finish strong and one day make it to the Major Leagues," Velazquez told MLB.com's Jesse Sanchez earlier this month in Arizona. "I feel like I had a good year and I just want to build on that."

Velazquez -- who is ranked No. 29 on MLB Pipeline's list of Top 30 Cubs prospects -- and Roberts brought the Cubs' 40-man roster to 37 players. Roberts had a 3.00 ERA with 72 strikeouts against 17 walks in 54 innings between Double-A Tennessee and Triple-A Iowa in 2021.

The lone Rule 5-eligible Top 30 prospect for the Cubs who was left unprotected was right-hander Riley Thompson (No. 28). Chicago rolled the dice with that decision, given that Thompson missed 2021 with shoulder issues and last pitched in the Minors at Low-A Myrtle Beach in '19.

Velazquez, on the other hand, was an easy roster add for the Cubs. The offensive spike that the 22-year-old outfielder enjoyed this season at High-A South Bend and Double-A carried over into the AFL.

Playing for the Mesa Solar Sox, Velazquez has slashed .366/.467/.693 with nine home runs, six doubles, 21 RBIs and 17 walks against 34 strikeouts through 26 games. Velazquez also made this year's Fall Stars roster and will play in the AFL championship game on Saturday.

With the Solar Sox, Velazquez has piled up 13 multihit games, including five games with at least three hits. That includes a three-hit outburst on Thursday, the eve of the Cubs' 40-man decisions. He belted his first AFL homer on Oct. 22, then proceeded to homer six times in a 10-game span.

"He's been amazing," Cubs president of baseball operations Jed Hoyer said at the General Managers Meetings last week in Carlsbad, Calif. "Listen, he had a really good year. So, this is a continuation of a really excellent season. I'm super proud of him."

Velazquez's AFL production comes after the outfielder (he mostly plays the corners, but has experience in center) hit .270 with 20 homers, 23 doubles, 73 RBIs and an .829 OPS in 103 games between High-A and Double-A this past season.

After posting a 33.7 percent strikeout rate in 69 games at High-A (.776 OPS), Velazquez moved up to Double-A, lowered his K-rate to 25.5 percent in 34 games and turned in a .938 OPS. His slugging percentage jumped to a combined .496 in 2021, which is up from .441 in '19 and .380 in '18.

"Things that I worked on during the quarantine," Velazquez told Sanchez in Spanish, "I have been able to do that in games."

Velazquez was a fifth-round pick by the Cubs in the 2017 MLB Draft -- the first high schooler taken by Chicago that year. During the '20 shutdown period, he remained at home in Puerto Rico, where he worked on his swing, focused on facing a pitching machine and aimed to improve his approach against breaking balls.

While the hitter-friendly Fall League can be challenging to evaluate, the fact that Velazquez's showing has built on an already-strong Minor League season helped grow the Cubs' determination to add him to the 40-man roster.

"You've got to judge the performance," Hoyer said. "You always have to think about guys like that. He's not old, but maybe it comes together a little bit later. Or [maybe] they weren't sort of a top, top Draft pick -- those kind of guys that come on late."

Hoyer referenced Cubs catcher Willson Contreras, who posted a .908 OPS in the AFL in 2015 and broke into the Major Leagues the following season.

"Willson's obviously a good example of that," Hoyer said. "It's been fun. I was at the Fall League [recently] and it was really good to see [Velazquez] playing that well. He's been as good as anyone in that league."

Rule 5 refresher

Players first signed at age 18 or younger must be added to 40-man rosters within five seasons or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 years or older have to be protected within four seasons.

Clubs pay $100,000 to select a player in the Major League phase of the Rule 5 Draft. If that player doesn't stay on the MLB roster for the full season, he must be offered back to his former team for $50,000.

For this year, that means an international or high school Draft pick signed in 2017 -- assuming he was 18 or younger as of June 5 of that year -- had to be protected. A college player taken in the 2018 Draft was in the same position.