Is there definitely an "awakening effect" after a trade?

Lee Woo-sung: Last year at Kia, batting average .250, OPS .670; this year at NC, batting average .305, OPS .754
Ha Ju-seok: At Hanwha until this June, batting average .256, OPS .589; after being traded to Kia, from July onwards, batting average .296, OPS .814. Even his defense has improved significantly.