I find this very doubtful. Obviously the middle ages doesn't have the sort of detailed economic statistics that allows us to calculate directly whether or not anything like modern day recessions was occuring or not. Economic historians are still debating questions like whether econoimc output rose or fell over periods of generations, let alone the more modern economic cycle of a few years.
That said, there is some evidence of economic fluctuations. Firstly in the middle ages, the economy was predominantly agricultural and thus output fluctated in line with the weather. Not only do lords and kings have no ability to control the weather, there is evidence that fluctuations in agricultural output caused social stresses (to put it mildly). Unusually cold weather during the growing season has been linked to persecutions of Jews over the period 1100-1800 (Anderson et al, 2017). There was a long-term decline in such persecutions (note of course that 1800 is well before the Nazis), which Anderson et al linked to greater state capacity over this time period. This in turn implies that the ability of lords and kings to control the actions of others in earlier times was less than it was in 1800, not more. The Middle Ages also saw numerous famines in all parts of Europe, the first disappearance of famines was in the Netherlands, where the last peacetime famine was in 1590. Maybe not the sort of recession that Wolff was thinking of, but clearly a source of instability in people's lives.
Secondly, economic historians have also found fluctuations in monetary prices, and credit availability, at least in Western Europe. Nightengale (2010) managed to study credit availability in medieval England quantitatively, using certificates of debts (the Statute Merchant and Staple certificates). Starting with legislation of 1284, the certificates record defaulted debts from across the kingdom which were sent to Chancery for enforcement by local sheriffs. They can also be linked to the death rate of creditors, allowing some control for changes caused by mortality highs for famines or epidemics. For example, the value of these certificates fell by 15% in the 1390s, without a rise in mortality, implying a reduction in credit due to a reduced output of silver coin and this was asssociated also with bankruptcies of some prominent London merchants, and other merchants requiring much higher collatoral. (A fair chunk of the problem of this time was that gold coins were too high value for the transactions needed for day to day life).
Thirdly, there is some reason to doubt the ability of lords and kings to control the economy. Trade, both of goods and services, and of money, flowed across Europe. For example, Francesco di Marco Datini, an Italian merchant in Patro (Italy), who traded from 1383 to 1410 and whose business records fortuitously survived, traded with people from Spain to Naples to Venice to Bruges to London, and many points in between. The ability of the kings of England or France to affect the lending practices of Italian merchants, or that of Italian princes to affect those of London or Paris, was presumably limited even at peaceful times. Let alone if there was a war going on. And that raises another question, how much ability would a lord or a king fighting against the Vikings, or the next door kingdom, or a civil war, have to control the local economy? Beyond this, we have evidence that monarchs would often grant various liberties and rights of self rule to medieval cities, which also argues against the lords and kings tightly controlling the economy. (The liberties of medieval cities is not my area of expertise, but it comes up in a lot of sources.)
So we have evidence of fluctuations in real output (due to the importance of agriculture), in prices and in credit availability. With all this, it would surprise me if there weren't recessions in medieval Europe, even discounting the direct costs of bad harvests.
Sources:
Robert Warren Anderson Noel D. Johnson Mark Koyam, (2017), Jewish Persecutions and Weather Shocks: 1100–1800, The Economic Journal, 127.602.
Bell, Adrian R.; Brooks, Chris; Moore, Tony K. Cambium non est mutuum: exchange and interest rates in medieval Europe, Economic History Review. May2017, Vol. 70 Issue 2
John Munro (2006), review of Stuart Borsch's The Black Death in Egypt and England: A Comparative Study, http://eh.net/book_reviews/the-black-death-in-egypt-and-england-a-comparative-study/
Jim Bolton (2013), review of Money in the Medieval English Economy: 973-1489, https://eh.net/book_reviews/money-in-the-medieval-english-economy-973-1489/
S. R. H. Jones, Transaction costs, institutional change, and the emergence of a market economy in later AngloSaxon England, Economic History Review, XLVI, 4(1993)5 PP- 658-678
Nightengale, Pamela. 2010. Gold, Credit, and Mortality: Distinguishing Deflationary Pressures on the Late Medieval English Economy. The Economic History Review 63 (4): 1081–1104. doi:10.1111/j.1468-0289.2010.00525.x