The Twins will call up Jax from Triple-A St. Paul to start the first game of Monday's doubleheader with the White Sox, Betsy Helfand of the St. Paul Pioneer Press reports.
Due to the twin bill, the Twins will temporarily have a need for a sixth starter, so Jax will return from the minors to fill the void. Jax previously made five appearances (one start) for Minnesota earlier this season, posting an 8.66 ERA and 1.70 WHIP across 17.2 innings.