The deal is pending exchange of medical information between the two clubs.
?A source said that minor-league pitcher Grayson Long will be going to Detroit in the trade. Long, a former 3rd-round pick, went 8-6 with a 2.52 ERA in 23 starts with the Angels' Double-A Mobile farm club this season.
It's uncertain if any other pieces will be going to Detroit in the deal.
Upton, 30, is hitting .279 with 28 homers and 94 RBIs this season. He's a four-time All-Star over 11 seasons with Arizona, San Diego and Detroit.
Upton signed a six-year, $132 million contract with Detroit in January 2016. He's owed $88 million over the next four seasons, but has the option to opt out of the deal in November.
The Athletic was first to report the pending trade between the clubs.
The Angels have weathered a slew of injuries to their pitching staff and are currently 69-63 and one game behind Minnesota in the race for the American League's second wild card spot. Upton adds a veteran power bat to an offense that ranks 12th in the league in runs (584) and 15th in OPS (.713).?
Upton has started 124 games in left field for Detroit this season and upgrades a position of need in Anaheim. Angels manager Mike Scioscia has used Cameron Maybin, Ben Revere and five other players in left this season. They've combined for a .244/.315./.341 slash line and hit seven home runs in 492 at-bats.