The 20-year-old Castro has been performing well at Triple-A Buffalo. He has 28 strikeouts in 24 2/3 innings and is averaging more than a strikeout per inning throughout his minor league career.
Smith opened the 10th inning in a tie game with two walks and a hit-by-pitch sandwiched around a strikeout. He was removed, but a sacrifice fly scored the go-ahead run and tagged him with the loss.
He has allowed three runs and taken two defeats in his last two appearances.
Montgomery wasn't lights-out, but he did allow just two earned runs on five hits in 6 2/3 innings in a no-decision against Arizona. He walked four and struck out five.
Home runs by Paul Goldschmidt and Welington Castillo in the first two innings appeared to have Montgomery reeling again. But he righted himself and later retired eight in a row.
Montgomery owns a 3.20 ERA, but hasn't won a game since July 5.
The 32-year-old Reyes owns a slash line on the year of .285/.333/.385.
Iwakuma has gotten into a groove after losing most of the season to injury. He is 2-0 in his last three starts with four runs allowed and 18 strikeouts in 20 2/3 innings.
Rodriguez hit his 24th home run of the season off Matt Harrison in the sixth inning. The solo shot was his only hit in five at-bats during the contest.
Prior to Monday's win, Rodriguez was hitting .286 with seven home runs and 11 RBI in his last 11 games.
Crisp played seven innings and also walked once and scored a run. Monday was his first rehab game since going on the disabled list in mid-May with a neck injury. He is expected to play three more games at Class A.
Gregorius smacked a two-run shot off Matt Harrison in the third inning for his fifth home run of the season.
Prior to Monday's win, Gregorius was hitting .256 with two doubles and two RBI in his last 12 games.
Harrison allowed six runs on six hits over six innings of work. He also struck out two and walked two. He gave up a two-run home run to Didi Gregorius in the third inning and a solo home run to Alex Rodriguez in the sixth. His ERA rose from 5.40 to 6.75.
Harrison (1-2) has one quality start over his three starts this season.
Robertson retired the first two Red Sox at Fenway Park before trouble ensued. A walk, RBI single to Pablo Sandoval and another walk allowed the winning run to come to the plate. But Robertson induced Ryan Hanigan to ground out to secure his 22nd save.
The right-hander has given up two runs on three hits and three walks over his last three appearances.