SANTA CLARA -- The 49ers will be forced to wait until training camp to see first-round pick Solomon Thomas on the field with his new teammates.

NFL rules prohibit rookies who have not completed their undergraduate degrees from joining a team’s offseason program on a full-time basis until after their schools' final classes of the spring semester.

Thomas, a defensive lineman chosen with the No. 3 overall pick, is not eligible to join the 49ers’ offseason program until Thursday, which was originally scheduled to be the team’s final day of on-field work during the mandatory minicamp.

Coach Kyle Shanahan has decided to hold practices Tuesday and Wednesday. Thursday will be set aside for meetings. Thomas will be allowed to attend meetings on Thursday. The team is then excused until the beginning of training camp in late-July.

This is the second year in a row that Stanford’s late class schedule will have an impact on the 49ers. Guard Joshua Garnett, a first-round pick last year, was allowed only to practice with his teammates for the team’s final minicamp in June.

Undrafted wide receiver Kendrick Bourne of Eastern Washington -- due to a late class schedule -- will not be allowed to join the 49ers until after the conclusion of the team's official offseason program.

Bourne and Thomas were permitted to take part in the rookie minicamp after the draft, but are the only rookies forced to remain away from the team for the duration of the offseason practices.