Injuries and films of Harvard's first three games have prompted coach John Yovicsin to readjust his depth chart for this Saturday's encounter with Columbia's hungry Lions.

Sophomore Ken Boyda, who has been more than impressive on defense this season, will move up to the first unit in the left and slot to replace Tom Stephenson. Stephenson received a knee injury early in the Cornell game and may be out of uniform for another week.

Another sophomore, Bob Barrett has zoomed through the ranks to take over as starting left guard from the injured Walt Dobrgelecki. Barrett introduced himself to Stadium-goers last Saturday by intercepting a Gary Wood pass and deflecting another. He undoubtedly will get many opportunities to try his luck at interceptions this week when Archie Roberts holds forth behind the light blue lines.

The third major change in the line-up is at right tackle, where Neal Curtin has been installed in the first unit. Yovicsin described Curtin's replacement of Joe Jurek on the starting team as a "merit promotion." Films have shown that Curtin has regained the form that made him the top freshman tackle two years ago. Last season he was waylaid by injuries. Jurek has on occasion had had difficulty defending his outpost

In addition to these changes Yovicsin has been re-arranging his defenses to meet the challenge of Columbia's balanced line, wing-T offense.