The first-half championship of the Southern League's South Division will go to the final day.
Mobile's 4-0 loss at Pensacola and Mississippi's 4-1 win at Tennessee on Sunday leave the first-place BayBears with just a half-game lead over the Braves.
The league ends the first half of its schedule Monday and the first-place teams in each division at the end of Monday's play are assured playoff berths.
Mobile is the two-time defending Southern League champion and the last three-peat was by the Montgomery Rebels from 1975-77. Mississippi last reached the playoffs in 2008.