Masterson (7-2, 2.83 ERA) won two starts over the week, tossing 16 scoreless innings, while striking out 20.
The right-hander is the second Cleveland player to win the award this season, joining outfielder Ryan Raburn. He is the first Indians pitcher to win the award since CC Sabathia in 2008.
Masterson, who is riding a 19-inning scoreless streak, is the first Indians pitcher to record seven wins through the first 42 games of the season since Charles Nagy went 7-1 over his first nine starts in 1996.
Of Cleveland’s record seven wins over former Cy Young Award winners before June 1, Masterson earned the decision in three against Toronto’s R.A. Dickey, Tampa Bay’s David Price and Seattle’s Felix Hernandez on Sunday.
The first Cleveland pitcher to log consecutive 200-inning seasons since Cliff Lee from 2005-06, Masterson leads the majors with 70 innings pitched.
Closer Chris Perez has allowed three home runs over his last two appearances, but the two-time All-Star isn’t sweating the subpar performance.
“It’s just one of those things,” said Perez, who is 2-0 with a 2.25 ERA in 16 games, converting six of his eight save opportunities. “I’m not one to watch a lot of video, but I’ll definitely be in (today) and see if I can find something. Maybe it’s a little mechanical thing after the shoulder hiccup. It’s a little slump. It happens once or twice a year.”
Indians manager Terry Francona is nowhere near considering other options in the ninth inning.
“That’s the nature of the game,” he said. “When you’re in that role and you give up a home run, it’s glaring. The good part is he feels good and he’s done this before. He’ll be a big part of what we do.”
Perez missed a large portion of spring training with a right shoulder ailment but says he is physically sound.
Right-hander Brett Myers (right elbow tendinitis) is scheduled to make his second minor-league rehab appearance Wednesday for Double-A Akron.
Myers, who tossed three scoreless innings in his first rehab appearance for the Aeros on Saturday, is expected to make one more after Wednesday before rejoining the Indians.
The first-place Indians host defending Central Division champion Detroit in a two-game series that begins tonight at 7:05.
Right-hander Corey Kluber (3-2, 5.40 ERA) opens the set against the Tigers, opposing RHP Max Scherzer (5-0, 3.98), while Ubaldo Jimenez (3-2, 5.31) starts for the Indians in the series finale Wednesday (7:05 p.m.) against Cy Young Award-winning right-hander Justin Verlander (4-4, 3.17).
The Indians improved to 15-8 at Progressive Field, entering the day with the third-best winning percentage (.636) at home in the American League behind Texas
(14-5, .737) and Detroit (13-7, .650).
Cleveland has won 13 of its last 15 games at home and leads the majors with 36 homers at home.
Prized pitching prospect Trevor Bauer’s control problems continued Sunday with the right-hander walking five batters over six innings in Triple-A Columbus’ 10-4 win over Scranton/Wilkes Barre. Bauer, who allowed four runs, has walked 10 batters in four starts (24⅔ innings) for the Clippers and 15 in his three spot starts (16⅓ innings) with the Indians.
* Left fielder Cord Phelps hit a pair of homers for Columbus. He is batting .234 with three homers and 16 RBIs in 28 games for the Clippers.
* Shortstop Jose Ramirez had four of Akron’s nine hits in a 6-4 loss to Erie on Sunday. Ramirez, a non-drafted free-agent acquisition in 2009, entered Monday batting .266 with a homer, 10 RBIs and 17 stolen bases in 34 games.
Cleveland is 10-1 against AL West opponents.
* The four-game sweep was the Indians’ first against the Mariners since August of 1981.
* Raburn is batting .636 (7-for-11) with three homers and 12 RBIs with runners in scoring position and two outs.