It must be the new exchange rate at the Canadian border.

John Tavares to Toronto, Leo Komarov and Matt Martin to Long Island.

The Islanders, who (in)famously lost their captain to the Maple Leafs via free agency on Sunday, reacquired popular hitman Martin from that same team on Wednesday in exchange for minor league goaltender Eamon McAdam.

Thus, coach Barry Trotz can put out Martin-Casey Cizikas-Cal Clutterbuck 2.0 in reassembling the unit that for a time was among the best fourth lines in the NHL when Jack Capuano was behind the bench. The problems are: a) that was three, four and five years ago, and b) the trio could become the Islanders’ third line.

Unless, that is, if Komarov, for whom major domo Lou Lamoriello wildly overpaid by signing the winger with a resume littered with cheap shots to a four-year, $12 million deal, plays in the top nine. He presumably would be paired with center and fellow free agent signee Valtteri Filppula, who works on a more tolerable one-year, $2.5 million contract. Of course, training camp is 11 weeks away.

Martin established himself as one of the Islanders’ most popular players throughout his initial six-year tenure with the club. He went to Toronto as a free agent two summers ago on a four-year, $10M deal, imported by then-Leafs GM Lamoriello in order to provide protection and leadership for that team’s emerging group of talented, young forwards.

But things appeared to pass the physical winger by last season. Martin played in just three of Toronto’s final 33 games after Jan. 22 and did not crack the lineup in the seven-game, first-round defeat to Boston. He got 9:00 or more of ice time in only 10 of the 50 games in which he dressed, while recording 12 points (4-8).

The 29-year-old, engaged to WFAN personality and former NFL quarterback Boomer Esiason’s daughter, Sydney, has two years remaining on his deal at an annual cap hit of $2.5M per. But the Islanders will owe him only $750,000 this year and $1.75M next year after the Maple Leafs paid his $1.5M signing bonus on July 1.

The Rangers, as reported here on Monday, checked in on Martin but ultimately decided to pass. Now they are scheduled to face him up to four times (twice at the Garden, twice at Barclays), presumably as part of the reassembled trio that owned the Blueshirts its final three years intact.

The Islanders signed goalie Robin Lehner to a one-year deal. The eight-year veteran, who turns 27 later this month, had been highly regarded early in his career with Ottawa, where he spent his first five seasons. Lehner was traded to the Sabres in 2015 for a first-round pick, and over three years in Buffalo, he went 42-61-22 with a 2.77 goals-against average and a .916 save percentage, including 14-26-9 with a 3.01 GAA and a .908 save percentage last season.