"(A third) of MLB teams had an off day on Jackie Robinson day," Price tweeted. "I just can't wrap my head around that. We've had a problem for a while and this couldn't make it any more noticeable."
Ten games were played Monday. The New York Yankees, Tampa Bay Rays, Detroit Tigers, Houston Astros, Oakland Athletics, Atlanta Braves, Washington Nationals, Pittsburgh Pirates, Arizona Diamondbacks, and San Francisco Giants all got the day off.
"No one should have an off day, let alone 10 teams," Price added.
Major League Baseball responded to Price's criticisms later Wednesday.
"In a perfect world, all teams would play on Jackie Robinson Day," MLB announced in a statement, according to Michael Silverman of the Boston Herald. "Unfortunately, there are some scheduling challenges when April 15 falls on a Monday, which is a heavy travel day for clubs.
"MLB worked with the clubs who were not playing on Monday to ensure that their players would wear 42 and have festivities on Tuesday to celebrate Jackie Robinson Day.
"While it is not ideal, one benefit is that this extends the celebration and awareness of Jackie Robinson Day over two days and guarantees that every one of our players participates."
All 30 clubs were scheduled to play on April 15 last season when the date fell on a Sunday. But five games were postponed due to weather so only 10 were played.
Price said he spoke with both Tony Clark of the MLBPA and commissioner Rob Manfred about his concerns. The Boston southpaw also recently criticized MLB for the manner in which it markets African American players.
Jackie Robinson broke baseball's color barrier and played his first major-league game on April 15, 1947.