NEW YORK -- The Yankees' search for high-end starting pitchers has delivered "The Big Maple" to the Big Apple.

New York acquired standout left-hander James Paxton from the Mariners on Monday evening for a package of three players, including top-rated southpaw Justus Sheffield .

Right-hander Erik Swanson and outfielder Dom Thompson-Williams were also sent to Seattle in exchange for the 30-year-old Paxton, who followed a breakout 2017 campaign by going 11-6 with a 3.76 ERA in 28 starts this past season, including a May 8 no-hitter over Toronto.

"I couldn't be more excited," Paxton said. "It's going to be a fantastic opportunity in New York, always expecting to win, just like I do. I expect myself to win, I expect the best out of myself. I'm just looking forward to being a part of such a fantastic team."

Though injuries have been a concern for the Canadian-born hurler, who has been on the disabled list five times in the last three seasons, Paxton set a career high this year with 160 1/3 innings while collecting his first 200-strikeout campaign, with 208.

"Health is a big part of it," Paxton said. "Having those larger chunks of time the last couple of years has allowed me come into my own and make some big strides. I think my best baseball is still to come."

Yankees general manager Brian Cashman said that he had been negotiating with Seattle counterpart Jerry Dipoto for about a month concerning Paxton, including during the General Managers' Meetings in Carlsbad, Calif.

The Astros' refusal to include Forrest Whitley -- their No. 2 prospect -- in an offer for Paxton precipitated the Mariners' decision to trade Paxton to New York, a source told MLB.com's Jon Paul Morosi.

"I believe he had a lot of different clubs he was talking to," Cashman said of Dipoto. "He was very disciplined throughout this process, which forced me to wait on it. We had a lot of different ideas go back and forth. Hopefully, both clubs get what they're looking for."

Cashman said that Seattle insisted upon the inclusion of Sheffield, the game's No. 31 prospect per MLB Pipeline. Sheffield becomes the top prospect in Seattle's system, having logged a 2.56 ERA with 84 strikeouts in 20 appearances (15 starts) for Triple-A Scranton/Wilkes-Barre in 2018.

"I was in my car and just got done playing golf," Sheffield said. "I saw Cashman's number pop up on my phone and immediately knew I'd been traded somewhere. It definitely caught me by surprise."

Paxton spoke to Cashman and Yankees manager Aaron Boone on Monday. He is slated to join Luis Severino and Masahiro Tanaka atop a rotation that features Carsten Sabathia near the back end. Cashman has spoken openly about his intent to trade Sonny Gray before next season.

Big Maple in the Big Apple. Welcome, @James_Paxton! pic.twitter.com/IlOtWehD03 — New York Yankees (@Yankees) November 19, 2018

With free agents Patrick Corbin and J.A. Happ among those on the club's radar, Cashman indicated that he wants to add at least one more starter via trade or free agency. He also hopes to make changes to the middle infield in the wake of Didi Gregorius' injury, and the bullpen.

"Pitching is the key area for us to address," Cashman said.

After posting 12 wins and a 2.98 ERA in 2017, Paxton remained a steadying force atop Seattle's rotation this year. Over parts of six seasons with the Mariners (2013-18), Paxton is 41-26 with a 3.42 ERA in 102 starts, posting a sub-4.00 ERA in each of those seasons.

"He's continuing to trend in the right direction," Cashman said. "I think he is establishing himself as a real quality left-hander in the game today."

The 2009 first-round Draft selection earned $4.9 million in 2018 and has two seasons of arbitration eligibility remaining before he can become a free agent. Paxton is projected by MLB Trade Rumors to earn $9 million in 2019.

"It seems to me that Seattle is trying to go young right now and building for the future," Paxton said. "My window is only for the next two years through arbitration, so I think that they're going young."

Acquired from the Rangers in the August 2016 trade of outfielder Carlos Beltran, Swanson had a breakout campaign in 2018, going 8-2 with a 2.66 ERA across three levels. He finished the year at Triple-A, where he was 3-2 with a 3.86 ERA in 14 games (13 starts).

Thompson-Williams, a center fielder, hit .299/.363/.546 with 22 homers in Class A and Class-A Advanced in 2018. He was a fifth-round Draft selection by New York in 2016.

One of four players acquired from the Indians in the July 2016 trade of left-hander Andrew Miller , Sheffield made three relief big league appearances in September. Cashman said that it was difficult to surrender Sheffield, but they believe Paxton will be able to help immediately.

"Sheff was a tough choice we had to make," Cashman said. "When we traded Andrew to get multiple pieces back, it was to try and address the rotation. With Paxton's addition, hopefully it pays off that way."