NEW YORK -- Clint Frazier's return to the big leagues highlighted the Yankees' first wave of September call-ups, and manager Aaron Boone inserted the big-swinging slugger into Sunday's lineup as the designated hitter against the Athletics.

Frazier, who turns 25 on Friday, batted .283/.330/.513 with 11 homers and 34 RBIs in 53 games for the Yankees this season. He hit .247/.305/.433 with eight homers and 26 RBIs in 61 Triple-A games.

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“He’s been working hard on his game and swinging the bat better after first getting down there and struggling a little bit," Boone said. "We know what he’s capable of, and the defensive part of it he continues to work very hard at. We know that he has the capabilities, and now hopefully he can come up here and continue to impact us like he did when he was here."

Frazier went 0-for-2 with a walk in the Yankees' 5-4 walk-off win over the A's, but Boone was encouraged by his at-bats.

"[He had] two sharply hit balls down the line to third. The first one [was] really hit hard. [He] was able to work the walk," Boone said. "Quality at-bats, good contact. Not a lot of results. I thought his at-bats were good."

While in the Majors, Frazier saw the majority of his time in right field, including a June 2 contest in which he misplayed three balls in a loss to the Red Sox. Frazier has said that his inconsistent fielding is what has kept him in Triple-A since his most recent big league contest on June 16.

In addition to Frazier, right-handers Chance Adams and Ryan Dull were recalled from Triple-A Scranton/Wilkes-Barre. The Yankees also signed left-hander Tyler Lyons to a Major League contract, selecting him from Triple-A.

“Most of those guys are capable of giving us more than an inning at a time, and those guys today certainly will be in place as we stay away from a few guys," Boone said. "Hopefully, they can provide us some depth and some options and hopefully help us win some games.”

In order to create space for Lyons on the 40-man roster, right-hander David Hale was transferred to the 60-day injured list. Boone said that more call-ups are on the horizon; catcher Kyle Higashioka will be on his way to New York when the Triple-A season ends, Boone said.

As the season's final month begins, here is a look at how the Yankees' farm system has made an impact in 2019:

Arrival: After more than 550 games over seven Minor League seasons, first baseman Mike Ford finally made his big league debut in April, a journey that began as a non-drafted free agent out of Princeton University. Finding a groove with increased playing time as an understudy to Edwin Encarnacion and Luke Voit, Ford enjoyed a recent stretch that included an Aug. 25 homer off the Dodgers' Clayton Kershaw and a multi-homer game on Aug. 26 at Seattle, as well as his first big league pitching appearance on Aug. 15 vs. Cleveland.

Breakout: Double-A Trenton first baseman Chris Gittens has been named the Most Valuable Player of the Eastern League. The 25-year-old entered play on Sunday batting .279/.391/.494 with 22 homers and 76 RBIs in 113 games. A 12th-round Draft selection in 2014, Gittens hit just .193 in an injury-marred 2018, and his big performance will prompt the club to ponder placing him on the 40-man roster to protect him from this winter's Rule 5 Draft.

Something to prove: Estevan Florial has been among the Yankees' top prospects for years, but the outfielder's progress was stalled in March when he fractured his right wrist in a Spring Training game. The 21-year-old hit .237/.297/.383 with eight homers and 38 RBIs in 74 games at Class A Advanced Tampa this season. Despite the tough year, Florial's five-tool potential continues to suggest that he can find big league stardom down the line.

Name to watch: Flame-throwing right-hander Deivi Garcia has been compared to a young Pedro Martinez and appears to be on the cusp of a big league call-up after rocketing from Class A Advanced to Double-A, appearing in the All-Star Futures Game, then earning a promotion to Triple-A. Though his initial results at Triple-A have not been great (5.84 ERA in 37 innings), general manager Brian Cashman has suggested that Garcia's electric arsenal could help the Yankees out of the bullpen as soon as this month.