Mets retire Willie Mays' No. 24 as Old-Timers' Day returns
Home Run Apple Commemorates No. 31 Retirement - Mets History
Mike Piazza's No. 31 retired by Mets
Why would the Mets wait so long to retire Mike Piazza's No. 31
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Mike Piazza Autographed Retirement Jersey - Mets History
The Mets retire Mike Piazza's Number 31 in 2016
Mike Piazza to Have No. 31 Retired by Mets: Date, Comments and
Mets' retired numbers
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