When I saw it, I said mouse ear chickweed. Google images of mouse ear chickweed seem to me to look just like what you have pictured. It can be controlled somewhat with 24DB but its fairly complicated to do it(has to be done at exactly the right time in a 4 leaf stage rosette). Best and most economical thing to do IMO would be to spot spray with gly if you can. It is a cool season plant so mowing may be just fine, although if it was me Id rather just kill it out.