Source: First-round pick Johnson to take physical Friday as contract signing seems imminent

Termarr Johnson,It appears Termarr Johnson is about to officially begin his professional baseball career and sign with the Pirates.

According to a source, Johnson, the Pirates' first-round pick and the fourth overall pick this season, is in Pittsburgh and will take his physical Friday. That is usually the last step taken before a player signs a contract.

Terms of a potential contract are not yet known. The fourth overall pick carries a slot value of $7,005,800, though the Pirates do have some wiggle room to go over that amount.

Johnson, an 18-year-old shortstop from Atlanta, was rated as the best hitter in this year's draft, according to Baseball America, and was seen by some as a dark horse…