It is a ballast penalty. If you are above a certain level ( 8 for rookie tier and 12 or 14 for pro) you receive a weight penalty in the form of added ballast for being above the maximum level for the tier
It shows the ballast your drivers have to carry on:
Team level cap in Pro Tier is 14, your team is level 19 so, to make your team perform equally to top Pro team, your drivers receive ballast.