The 1938 season was the least productive of Keeton's first-class career: he made 1512 runs at an average of 29.07, the only time his batting average dipped below 30 in a full season of cricket. "Wisden" noted that "after an indifferent start Keeton went through other spells of mediocrity", but added that he had been "perhaps not in the best of health judging by the necessity of an operation for appendicitis in October". But he returned to health and form in 1939 with an average for the first time over 50: 1765 runs at 51.91. The runs included the Nottinghamshire record score of 312 not out, which was made at The Oval against Middlesex because Lord's, the usual Middlesex home ground, was required by its owner, the MCC, for the Eton v Harrow match. The innings lasted seven hours and a quarter and included 28 fours and a five, and Keeton was missed four times in the course of it. Keeton's form across the season led to his recall for a second Test match: the final game of a three-match series with the West Indies. In a game of high scoring, he was not successful, being out without scoring in the first innings and making only 20 in the second; it was the last Test match played before the Second World War and was also the end of Keeton's limited Test career. But after his most successful season so far, Keeton was named in the 1940 edition of "Wisden" as one its Cricketers of the Year.