Resides in Santo Domingo, Dominican Republic...His father, Francisco Montero, pitched in the Phillies organization (1996-2000).
Entered the season rated as the No. 5 prospect in the Cardinals organization by Baseball America, the "Best Hitter for Average" and "Best Infield Arm" in the organization...Participated in early workouts and seminars as part of the Cardinals Spring Training Early Program (S.T.E.P.)...Played the majority of an injury-shortened season with Springfield (AA), hitting .188/.235/.317 (42-224) in two stints covering 59 games....Began the year as the Texas League's fifth-youngest player (20.6) on Opening Day. Teammate Dylan Carlson was the 4th-youngest (age 20.4), born two months later on Oct. 23, 1998...Hit .219 (16-73) with two home runs in initial 18 games before placed on the injured list with a sprained wrist (4/27)...Activated (5/19) and played in seven games before returning to the injured list with a broken left hamate bone (5/29)...Rehabbed with GCL Cardinals for four games (7/22-7/26)...Rejoined Springfield (7/27) and hit .164 (21-128) over his final 34 games...After the season, rated as the No. 12 prospect in the Texas League in Baseball America's Best Tools Survey...Played for the Glendale Desert Dogs in the Arizona Fall League, hitting .200/.333/.300 (10-50) with three doubles, one triple and one RBI in 15 games...Had contract purchased and added to the 40-man roster with pitchers Alvaro Seijas and Jake Woodford (11/20).
Midwest League Mid-Season and Post-Season All-Star, and became the first Cardinal to be named Midwest League Most Valuable Player since Albert Pujols (2000)...Led the Cardinals minor league organization in doubles (37) and ranked among leaders in hitting (.315, 7th), runs (81, 3rd), hits (151, 2nd), homers (16, 8th), total bases (242, 2nd), RBI (82, 2nd), SLG (.504, 7th) and OPS (.875, 10th)...Paced the Midwest League in hitting (.322), slugging pct. (.529) and OPS (.910), ranked 3rd in total bases (202), 6th in on-base pct. (.381), RBI (69) and extra-base hits (123)...Hit cleanup and started at 3rd base for the West Squad in the Midwest League All-Star Game (0-for-2)...Named Midwest League Player of the Week for the July 2-8 period. Hit .400/.464/.720 (10-25) with two homers and nine RBI in six games...Posted a team-best 14-game hitting streak from 6/23-7/8, batting .415 (22-53)...Recorded both the longest home (20G, 5/2-6/13) and road (18G, 6/17-end of season) hitting streaks in the league...Set single-game career highs with two home runs (2) at Lansing (7/19) and four doubles at Clinton (7/29)...Promoted to High-A Palm Beach (8/7), hitting .286/.330/.409 (28-98) with a homer and 13 RBI in his final 24 games...Hit .500 (4-8) in two postseason games for Palm Beach...Following the season, ranked by Baseball America as the Midwest League's "Best Defensive Third Baseman" and No. 9 overall prospect.
Named a Gulf Coast League Post-Season All-Star, playing nearly the entire GCL season at age 18...Led the Gulf Coast League in sacrifice flies (6), tied for the league lead in extra-base hits (22), and ranked 3rd in RBI (36), 4th in doubles (16), and 6th in total bases (81)...Ranked among the Cardinals minor league leaders in slugging (.468, 9th) and OPS (.838, 7th)...Hit a grand slam off Tomas Alastre and had 5 RBI at GCL Nationals (8/5)...Following the season, Baseball America ranked him as the No. 9 overall prospect in the Gulf Coast League.
Hit .260/.349./352 in 61 games for the Dominican Summer League Cardinals, his second season with the club.
Played his first professional season for the Dominican Summer League Cardinals at the age of 16...Batted .328 with runners in scoring position.