You could definitly plant clover this spring - IF

you can effectively kill/plow/disk the existing sod. Planting on heavy sod is tough the first year because the weed root systems can be extinsive. - and even with 1/2 way good tilling - have a tendency to try to re-establish. Rye and or Buckwheat can inhibit this growth - and help eliminate it for year 2.

If you get it tilled good, or use roundup - then work the soil - you have a good chance with a Spring planted clover. But - it has to be planted early to take advantage of the cool weather.

FH