Almora, whom the Cubs chose with the sixth overall pick in Monday's first round, has committed to the University of Miami.
Almora previously said, "My main priority right now is college," but added: "I guarantee that I'm ready for Major League Baseball, but we'll have to see what happens with the time."
Almora, who prepped at Florida's Mater Academy, was rated highly on numerous Draft boards. The 6-foot-2, 180-pound center fielder was ranked as the Draft's No. 9 overall prospect by MLB.com's Jonathan Mayo.
He hit .603 (44-for-73) with 13 doubles, five triples, six home runs and 34 RBIs in 25 games for Mater Academy last season. He posted a 1.164 slugging percentage and a .667 on-base percentage, drawing 14 walks compared to only three strikeouts. He also stole 24 bases in 25 attempts.
Cubs manager Dale Sveum watched a lot of video of Almora and said he was impressed with the young outfielder.
"He's a pretty nice talent," Sveum said. "That guy is pretty far ahead in the game. His hitting mechanics I really like, and I think it's a very effortless-type swing. He does a lot of good things a lot of good hitters do."
Although the Cubs might have had their eyes on Almora for a while, he said he had no idea where he would go, saying getting the call was "a little overwhelming."
Almora also promised to show off the work ethic that made the Cubs think so highly of him.
"All I can guarantee is that I'm going to play the game 120 percent every time," Almora said. "I can't guarantee that I'll hit four home runs every day, but I'll be out there giving it my all every day and know what to do and have success doing it."
Despite being the first pick of the Cubs' new regime under president of baseball operations Theo Epstein, general manager Jed Hoyer and vice president of scouting and player development Jason McLeod, Almora said he feels no added pressure.
"No, I'm just happy to be picked by a Major League club," Almora said. "It's something I've worked for my whole life, and I'm just happy I've got there."