The Mets’ offseason rotation overhaul appeared complete Friday with the addition of another veteran arm.

Taijuan Walker, one of the few proven options remaining on the free-agent market, reached agreement with the Mets on a two-year contract worth $23 million, according to industry sources. The deal includes a third-year player option that starts at $6 million, with escalators than can increase it to $8.5 million, There is also a $3 million buyout of the player option.

Walker, 28, split last season between the Blue Jays and Mariners and finished 4-3 with a 2.70 ERA and 1.163 WHIP in 11 starts. He previously spent three seasons with the Diamondbacks.

“Taijuan, just looking at the history and his season last year, everything that he can bring to a team is pretty outstanding,” manager Luis Rojas said. “You talk about talent plus experience and around the league, players that have been in the same clubhouse with him, we heard about some leadership in there as well.”

The deal comes two weeks after the Mets missed on Trevor Bauer, who was the top free-agent starting pitcher on the market. Bauer had narrowed his choices to the Dodgers and Mets, but opted to remain at home in Southern California. The Mets also bid on left-hander James Paxton, who last weekend agreed to a deal with the Mariners. The Mets also sowed interest in starters Jake Arrieta and Jake Odorizzi at various points this winter.

Walker slots in behind Jacob deGrom, Carlos Carrasco and Marcus Stroman, with left-handers David Peterson and Joey Lucchesi among the candidates for the fifth spot in the rotation. Noah Syndergaard, who is rehabbing from Tommy John surgery, could rejoin the rotation by June.

“[Walker] can be a great addition as a guy that can definitely help a rotation and it can be a great asset,” Rojas said. “When we talk about having a deep rotation, it can always be a great piece for any rotation.”

Walker’s multi-year contract provides a level of protection for the Mets, as Stroman and Syndergaard can become free agents after the season.

The Mets’ payroll with Walker’s addition, for luxury-tax purposes, stands at $195 million. Teams are taxed at 20 percent for every dollar they spend over $210 million, and team president Sandy Alderson has said that plateau is a significant line of demarcation.

The possibility exists for the Mets to surpass the luxury-tax threshold without even adding another player, as they look to sign Francisco Lindor and Michael Conforto to contract extensions before Opening Day.

— Additional reporting by Joel Sherman