Hartman, 24, would arrive in Barcelona from Burnley, while an academy graduate heads the other way as part of the arrangement. According to La Grada, that player is 19-year-old attacking midfielder Lluc Castell, who would move to the Championship side.
The left-back joined Burnley from Feyenoord for around 10 million euros last summer, but found regular football hard to come by as the season unfolded. He started well and provided assists during the early months, but lost his place to Lucas Pires as Scott Parker's side stumbled toward relegation, ultimately finishing among the Premier League's bottom three.
Both Espanyol and Burnley are owned by Alan Pace, a link that has already produced a similar swap once before, when winger Luca Koleosho moved between the clubs in 2024, and appears to be shaping recruitment strategy on both sides of the deal.
Castell, formed at Espanyol's La21 academy after coming through the youth ranks at UE Sitges and Nastic de Tarragona, made his senior debut for the first team in May and has represented Spain at under-17 level. He is contracted at the RCDE Stadium until 2027 with an option for a further year, and the move to England is being viewed internally as a chance to accelerate his physical development in a more demanding league before potentially returning.
For Espanyol, Hartman would fill the left-back vacancy left by Carlos Romero, who returned to Villarreal after his loan spell in Catalonia expired, giving sporting director Monchi a direct replacement with Premier League experience, even if the exact structure of the deal, whether permanent or another loan, is yet to be confirmed.
Neither deal has been formally completed, but with talks described as being in their final stages, an announcement on both switches is expected in the coming days.