The winger left Norwich City in January to join Swansea on a six-month deal, but he couldn’t earn an extension to an injury-hit spell in South Wales.
He’s been offered a second-tier lifeline by the U’s, however, who are looking to bolster their squad after promotion from League One via the play-offs.
He could reunite with his former club as soon as August 10, when Oxford welcome City to the Kassam on the opening day of the season.
They lost Placheta’s fellow ex-Canary Josh Murphy to Portsmouth after the end of his contract this summer, and it’s hoped he’ll replicate the considerable success Murphy found after joining the club in 2022.
The Pole will be aiming for consistent game time after years in and out of the side under three different head coaches at Carrow Road, and he’s delighted to have joined their divisional rivals.
“I’m very happy to be an Oxford United player and I can’t wait to play in front of the fans and meet my new teammates,” he told their official club channels.
“I know I can be a good player in the Championship. My strengths are my dribbling, speed and directness and I know what the gaffer expects from his wingers.
“I want to add goals and assists to this team and I will do everything for the club to have a successful season.”
Head coach Des Buckingham added: “We are extremely pleased to have a player of Placheta’s quality in our squad for this Championship season.
“He offers incredible pace in our wide area and fits the profile we are looking for in our wide players.
“To add another player to the squad that has experience at this level is really important, and we believe Przemyslaw can make a big difference going forward and be a player that gets fans off seats.”
The 26-year-old joined Norwich from Slask Wroclaw in 2020, making 61 appearances and scoring twice. He helped them to a second title-winning promotion in three years in his first season at the club, albeit as a bit-part player after Todd Cantwell hit form.