Yordan Alvarez homered again and Jack Mayfield hit three doubles as Houston's rookies delivered in a big way, leading the Astros over the Toronto Blue Jays 7-2 on Saturday.

Alvarez became the fourth player in major league history to hit four home runs in his first five games. The 21-year-old from Cuba sent a solo drive into the upper deck in right field and finished with three hits, making him 8 for 17 in his brief career — he has driven in eight runs, scored eight times and also has drawn six walks.

The 28-year-old Mayfield was 2 for 34 as a big leaguer before breaking loose.

Houston Astros' Yordan Alvarez, right, celebrates his solo home run off Toronto Blue Jays starting pitcher Clayton Richard with Josh Reddick during the third inning of a baseball game, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Houston Astros' Yordan Alvarez, right, celebrates his solo home run off Toronto Blue Jays starting pitcher Clayton Richard with Josh Reddick during the third inning of a baseball game, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Framber Valdez (3-2), another rookie, struck out eight in six solid innings. The 25-year-old lefty allowed two runs and four hits.

Valdez had his second straight solid start since moving into the rotation. He gave up one run in seven innings in his first on Saturday against the Orioles.

Josh Reddick also homered for the AL West-leading Astros.

Houston Astros' Jack Mayfield (9) slides safely into second for a double, beating the tag of Toronto Blue Jays second baseman Eric Sogard during the sixth inning of a baseball game, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Houston Astros' Jack Mayfield (9) slides safely into second for a double, beating the tag of Toronto Blue Jays second baseman Eric Sogard during the sixth inning of a baseball game, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Clayton Richard (0-3) yielded five runs and seven hits in five innings. The left-hander struggled for a second straight outing after being tagged for seven runs in 2 2/3 innings in his last start Sunday against the Diamondbacks

Mayfield hit an RBI double in the second and came around to score on an error to give the Astros a 2-0 lead.

Myles Straw hit an RBI double and Alex Bregman followed with an RBI single to increase the lead to 5-0 in the fourth. Straw added an RBI single in the sixth.

Houston Astros starting pitcher Framber Valdez delivers during the first inning of a baseball game against the Toronto Blue Jays, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Houston Astros starting pitcher Framber Valdez delivers during the first inning of a baseball game against the Toronto Blue Jays, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Brandon Drury had an RBI single, and Eric Sogard followed with a sacrifice fly in the fifth to cut the lead to 5-2.

TRAINER'S ROOM

Blue Jays: 3B Vladimir Guerrero Jr. (bruised left hand) was out of the lineup after being hit by a pitch in Friday's game. Guerrero took batting practice prior to the game. . RHP Nick Kingham was activated prior to the game and gave up Reddick's leadoff homer in the sixth. RHP Thomas Pannone was optioned to Triple-A Buffalo. .. RHP David Phelps (Tommy John) threw a bullpen session Saturday. .. RHP Jacob Waguespack (shoulder) is scheduled to pitch two innings Sunday for Buffalo. ... LHP Ryan Borucki (elbow) was expected to throw live batting practice Saturday in Florida.

Toronto Blue Jays starting pitcher Clayton Richard delivers during the first inning of a baseball game against the Houston Astros, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Toronto Blue Jays starting pitcher Clayton Richard delivers during the first inning of a baseball game against the Houston Astros, Saturday, June 15, 2019, in Houston. (AP PhotoEric Christian Smith)

Astros: 2B Jose Altuve (left hamstring strain) had the day off before continuing his rehabilitation assignment with Triple-A Round Rock on Sunday. ... RHP Collin McHugh (right elbow discomfort) will pitch again for Round Rock on Monday. Manager AJ Hinch said Altuve felt "really good" after playing Friday. . CF Jake Marisnick (left knee discomfort) was out of the lineup Saturday after leaving Friday's game. "I think we have avoided a major issue," Hinch said.

UP NEXT

Blue Jays: RHP Trent Thornton (1-5, 4.78 ERA) will make his 15th start Sunday after allowing at least three runs in each of his last four outings.

Astros: RHP Brad Peacock (6-3, 3.42) starts Sunday looking to continue his recent success, which has seen him win four of his last five decisions.