Matt Joyce is coming off another outstanding month of May which is nothing new for the Rays outfielder. During the 2011 season the folks over at Draysbay.com gave him the nickname MOM (Month Of May) because his numbers in that month stand out as among the best in baseball. In 2011 his number in May were so strong they carried him to his first all star game selection despite a horrific June and in 2012 injury hit him in both June and July and he wasn’t able to sustain the level he had in May.
He is off to another great start for the Tampa Bay Rays and despite being used almost exclusively against right handed pitchers he is tied with Kelly Johnson  and Evan Longoria for the team lead in home runs with 10. Overall he has posted an impressive slash line (batting avg/on-base%/slugging%) of .258/.342/.510 and an OPS (on-base% + slugging%) of .853.
His month of May was once again very strong posting a slash line of .299/.396/.584 with 5 home runs and 17 RBI. The question that Joyce has to answer is can he sustain the good start through the summer months?
Month of May Since 2010:
Of all players with at least 275 plate appearances in the month of May since opening day 2010 he ranks 2nd with an OPS of 1.041 with a slash line of .333/.431/.610. He is in some very good company as shown in the table below:
2013: Another Fine Start, Another Stellar Month Of May
The table below shows Joyce’s numbers thus far through April and May of this season. From Fangraphs.com stat glossary  wRC+ measures how a player’s weighted runs created (wRC) compares with league average. League average is 100, and every point above 100 is a percentage point above league average. For example, a 125 wRC+ means a player created 25% more runs than league average.
2012: Good Start Short Circuited By Injury?
He got off to another hot start in 2012 posting a wRC+ of 169 in April and 158 in May. He still had a productive June with a 113 wRC+ but on June 20th he suffered an oblique strain which caused him to miss 27 days. When he returned he was unable to get back the swing that he had prior to the injury putting up a wRC+ of 86 in July, 74 in August, and 79 in September. He may have also been bothered by a bad back that forced him to miss a game shortly after he returned from the disabled list.
2011: Blistering Start Leads To All Star Game, Strong Finish Follows Mid-Summer Slump
He appeared to be having a coming out party in 2011. His April was impressive with a 146 wRC+ but his May was just off the charts with a wRC+ of 232. His April and May were so incredibly good that he was named to his first AS team despite his numbers falling off the cliff in June. There really is no explanation for what happened to him in June and July of the 2011 season but he recovered without explanation in August and September.
The hope is that the post-May slump in 2012 was health related and the post 2011 slide was a function of pitchers adjusting to him and him not adjusting back. What would Matt Joyce’s numbers look like if he could remain healthy and productive for a full season? The Rays certainly would like to find out and if he can develop consistency it would go a long way to helping the Rays sustain the surprising showing by their offense in 2013.