Happ has a 3.54 ERA in 11 starts this season, with 60 strikeouts and just 14 walks.
The 34-year-old became just the sixth Blue Jays pitcher to win 20 games in a season, going 20-4 with a 3.18 ERA in 2016.
Rosenthal says a trade involving Happ is “highly unlikely” however, given Toronto’s desire to compete in the 2018 season – for which Happ is under contract.
The Peru, Iill., native will be owed $13 million in 2018, and with a relatively weak crop of free agent pitchers on the horizon, Blue Jays GM Ross Atkins might be averse to trading a quality starter if he believes his team can make the playoffs next season.
Atkins has yet to sell any significant pieces of the Blue Jays roster, though that time might come soon ahead of July 31’s trade deadline.
Toronto is at the bottom of the A.L. East with a 42-48 record.