Alpine has loaned out reserve driver Paul Aron to drive for Sauber at practice sessions at upcoming Formula 1 events in Silverstone and Budapest.
The Estonian driver will make his debut for the team in Friday's practice for this weekend's British Grand Prix.
Sauber, still without a reserve driver for the season, needed a rookie to compete in two FP1 sessions this year, per the regulations.
Aron's deal will increase intrigue around Alpine's driver line-up.
Alpine replaced Jack Doohan with Franco Colapinto at Imola, but the Argentine has failed to live up to the lofty expectations created by his successful run with Williams last year.
De facto team boss Flavio Briatore has suggested Colapinto's performances need to improve if he wants to see out the season.
Sources have told ESPN Alpine are considering a third driver change if there is not a major turnaround from Colapinto, who is still yet to score a point since his debut with the team.
Aron getting two practice appearances in the races leading into the summer would open up speculation Alpine would look to make a change during August's four-week break.
There are other options should Alpine want to make a change.
According to The Race this week, Mercedes junior driver Valtteri Bottas is being lined up for a similar role. Alpine is set to switch to Mercedes power for 2026, which might make a deal easier to facilitate.
Aron finished third in Formula 2 last year, but has not been racing competitively in 2025.
Aron will drive Nico Hülkenberg's car at both Silverstone and Budapest, before handing back to the German driver for the rest of the weekend.
F1's rules say two rookies have to fill four FP1 appearances throughout a season.
Hulkenberg's teammate Gabriele Bortoleto is a rookie, therefore has already covered the requirement for the other other two days.