Peguero began his professional career in with the Dominican Summer League, batting.251 in 59 games. In he finished tied for first in home runs with seven, tied for second in triples with seven, second in extra base hits with 24 and tied for ninth in average with.313 in the Arizona League. Peguero hit safely in 23 of 34 games. He hit a home run in his second at-bat of the season on June 23 against the Arizona League Angels. He went 3-for-4 with two runs, two home runs and two RBIs on June 30. He hit three home runs in a five-game span from July 29 to August 2. He recorded 11 multi-hit games, including three three-hit games and a season-high four hits on August 1. He had four games with season-high three RBIs. On August 8 he was promoted to the Rookie-level Everett AquaSox. At the end of the season he participated in the Mariners Arizona Fall League. In, Peguero appeared in 79 games with the Single-A Wisconsin Timber Rattlers. He hit.407 during seven-game hitting streak from May 4–9. He went 3-for-5 with four RBIs on May 12. He recorded season-high eight-game hit streak, hitting.364, from June 11–21. He knocked in a career-high seven RBIs, going 3-for-5 with a two-run double, a three-run double and a three-run homer on June 15 against the Cedar Rapids Kernels. Peguero was on the disabled list with a left elbow strain from July 31 through the end of the season. He was named Wisconsin's Most Valuable Player by the Seattle Mariners. He participated in the Mariners' 2007 Arizona Fall League and played in the Dominican Winter League. Peguero spent the season with High Desert. He had 17 multi-RBI games, including a season-high four RBIs on April 3. He recorded a season-high four hits on June 17. Peguero was placed on the disabled list on July 17 for the remainder of the season, with a sprained left wrist. He participated in the Mariners' Advance Development League in Peoria, Arizona.
The Kansas City Royals acquired Peguero from the Seattle Mariners on January 29, 2014 for cash considerations. The Royals designated him for assignment on March 25, 2014, after they acquired Patrick Schuster off waivers, in the hopes that Peguero would clear waivers so they could assign him to the Omaha Storm Chasers. He was released by the Royals on December 19, 2014.
Texas Rangers
Peguero signed a minor league deal with the Texas Rangers on January 13, 2015. He was called up on April 11, and made his Rangers debut the same day. He was designated for assignment on May 20.
Boston Red Sox
On May 27, 2015, the Boston Red Sox acquired Peguero for cash considerations. On June 4, Peguero was designated for assignment, but rejoined the team by signing a minor league contract on June 15.
St. Louis Cardinals
The St. Louis Cardinals announced on January 22, 2016, that they signed Peguero to a minor league deal with an invitation to major league spring training camp. His minor league totals in 10 previous seasons included a.273 average,.335 OBP and.511 SLG. The Cardinals assigned him to the Triple-AMemphis Redbirds of the Pacific Coast League, where he batted.283,.355 OBP and.435 SLG.
On February 19, 2020, Peguero signed with the Pericos de Puebla of the Mexican League. Peguero was released by the Pericos on June 25, 2020.
Personal life
Peguero is married to Maria Jacqueline Peguero, the youngest daughter of former major league relief pitcherPedro Borbón, and sister of Pedro Borbón, Jr., also a former major league relief pitcher.
