The late Roland Hemond, a legendary and longtime general manager, used to say the trades that worried him the most were the ones in which he was lavished with immediate praise for having made a one-sided deal.

Under the Hemond proviso, the Mariners should be quite worried right now, because their trade on Wednesday with the Toronto Blue Jays for Teoscar Hernandez seems heavily weighted in their favor. That seemed to be the instant feedback on social media and beyond.

The Mariners gave up reliever Erik Swanson and minor-league pitcher Adam Macko to get Hernandez, the sort of highly productive power bat for which they have been clamoring. In present-day value, this trade is a home run for the Mariners (who no doubt remember the two home runs Hernandez hit against them in Game 2 of the American League Wild Card Series in October).

Swanson was outstanding as a high-leverage reliever in 2022, but by the postseason, manager Scott Servais appeared to have lost trust in him. Swanson didn’t appear in the Wild Card Series with Toronto, including Seattle’s clinching 10-9 victory in which the Blue Jays bullpen imploded in blowing an 8-1 lead. The Mariners used eight pitchers in that game before Swanson, including starter George Kirby to close it out.

Swanson’s only postseason appearance, in fact, was a scoreless 12th in the Mariners’ 18-inning loss to Houston that ended their season. His 1.68 ERA in 57 regular-season games, with 70 strikeouts and just 10 walks, was commendable and invaluable to their success. But one thing the Mariners have shown under president of baseball operations Jerry Dipoto and general manager Justin Hollander is that power arms in the bullpen are somewhat of a fungible product. They have a knack for unearthing them and will now be tasked with doing so again.

As for Macko, he is a classic play for the future by Toronto — an undeniably lively left-handed arm who could develop into a front-of-the-rotation ace. If that happens, remember Hemond’s words in two, three or four years down the line.

Macko could also fall anywhere below that, up to and including a total washout. At age 21 — with no experience above A ball, a history of arm and control issues but explosive stuff that makes scouts take notice — it’s impossible to know where Macko will fall on the spectrum of major-league productivity.

But Hernandez is far more of a proven commodity, having established himself as one of the most dangerous power hitters in the American League over the past five years. He’s averaged 26 homers over the past four full seasons, and in 2021 he hit .296 with 32 homers and 116 runs batted in, earning a starting spot in the American League outfield at the All-Star Game.

Jesse Winker is recent proof that statistical dominance does not necessarily transfer to a new team. But Hernandez, at age 30, seems certain to help fulfill this team’s biggest need — beefing up the offense.

Hernandez is also a potential free agent after the season. Don’t worry too much about that. This is precisely the sort of trade a team that is trying to get beyond the divisional round of the postseason makes. It perhaps signals that the Mariners have moved beyond always thinking about the future in every transaction to focusing on winning now — a significant advancement in their team-building evolution.

“When you get to the point where you come out on the other side of a rebuild, and you’re ready to be good, your roster tells you it is time to act in a certain way or not,” Hollander said Wednesday during a Zoom call. “It’s not usually something we’ve done to acquire a player with short control. A year at well-paid rates for Teoscar Hernandez hasn’t been something that we would have done in 2019 or ’20, or maybe even ’21.

“Our roster was different then; our roster now is built to win today. And myself, Jerry, our entire baseball operations group has to be responsive to that. And that’s the reality of coming out of rebuilds. We’re not looking to perpetually rebuild. We’re looking to be good and stay good, and we think Teoscar will help us with that.”

The contract extension given midseason acquisition Luis Castillo (who was born 58 days and 90 miles apart from Hernandez in the Dominican Republic, also the homeland of Hernandez’s new outfield partner, Julio Rodriguez) shows the Mariners are not averse to working out an extension if the fit is right. Hernandez has a reputation as a positive clubhouse presence, and the Mariners believe they are building a foundation that will make them increasingly attractive to potential free agents.

“The thing that’s been so exciting about Teoscar is the level of joy that he plays with, and the smile that he brings to this game,” Toronto general manager Ross Atkins told reporters Wednesday. “What that means to the Toronto Blue Jays, what that means for his teammates in the clubhouse, has been significant. He’s also been extremely productive, especially over the last three years.”

Even if Hernandez is a one-and-done rental, the trade will be worthwhile if it helps the Mariners get past the Astros in the AL West or fuels a long postseason run. If he signs elsewhere for 2024 and if the Mariners had tendered a qualifying offer, they would receive a draft choice around the 75th pick in 2024.

The Mariners, of course, now have even more of a glut of outfielders to sort out around the anchor in center field that is Julio Rodriguez. Winker, Kyle Lewis, Jarred Kelenic, Taylor Trammell, Dylan Moore and Sam Haggerty, among others, are all on the roster, at least for the time being, and free agent Mitch Haniger is still a possibility to return.

This is just the start of the offseason roster reformation by the Mariners, who are still trying to solidify their middle infield and now must fortify their bullpen. I suspect Messrs. Dipoto and Hollander will be among the most active executives in baseball over the coming months; 1) because that’s their penchant, and 2) because of the knowledge that this Mariners team could be a real powerhouse with a few bold moves.

Call this Bold Move No. 1. Who knows? Hemond’s instincts might be proven right over the long haul. But for a team trying to make a splash in 2023, it’s a great start to the Hot Stove season for the Mariners.