From 2015 until the trade deadline last season the Rays were one of the best offenses in the league against left handed pitchers. Over one and a two-thirds seasons the Rays put up a .263/.329/.438 line and 111 wRC+. Their 111 wRC+ only trailed the Blue Jays at 115 during that span.
At the deadline the Rays shipped out two productive bats against southpaws, Brandon Guyer and Steve Pearce. Pearce was a free agent at the end of the season, but Guyer would still have been under team control.
Guyer hit .289/.412/.490 and put up a 156 wRC+ that was tied for twelfth best in MLB with at least 200 PA against LHP.
Also making appearances in the top 20 are Logan Forsythe (11th, 160 wRC+) and Evan Longoria (16th, 149 wRC+).
After dealing Guyer and Pearce the Rays struggled as a team against lefties. From August 1st until the end of the season the Rays hit .234/.289/.378 and put up an 82 wRC+. That was good for 22nd in the league.
During that time period five Rays received at least 50 PA against lefties and that included Brad Miller (73 PA, 69 wRC+), Evan Longoria (63 PA, 45 wRC+), Corey Dickerson (62 PA, 71 wRC+), Logan Forsythe (53 PA, 53 wRC+), and Kevin Kiermaier (53 PA, 136 wRC+). Surprisingly Kiermaier was the only productive bat. Longoria and Forsythe really struggled.
The Rays had to throw Miller and Dickerson into the lineup almost every day due to injuries after the Rays removed their platoon partners at the trade deadline. It’s no real surprise they struggled, but they should see as little time as possible against LHP next year if the Rays want their offense to improve.
The Rays need to add at least one right handed bat to add to combat the Red Sox four left handed starters. The Rays currently have two left handed batters, Dickerson and Miller, who should be platooned more often than not. Kiermaier brings enough defensive value that you can afford to play him every day even if it’s lower in the lineup.
The Rays have already added Wilson Ramos to the roster and he will likely see some DH time as he works his way back from a torn ACL. Ramos’s 117 wRC+ against lefties makes his bat useful if he’s able to transition well to the DH.
In an alternate universe, the Rays could add a bat like Jose Bautista who you could throw in LF for 50 games and then 100 games at DH, and who would add the punch needed against pitchers of both hands. Bautista’s 103 wRC+ against LHP that he posted in 2016 was one of the worst of his career. He’s put up a 135 wRC+ for his career and 130 wRC+ in 2015.
The likely scenario is they add some high variance, expendable bat like a Trevor Plouffe or Dae-Ho Lee who can easily be dropped when Ramos is ready to see some DH time should he fail to produce.
Primarily, however, the Rays need to count on increased production against LHP from Forsythe and Longoria. Longoria’s 94 wRC+ against lefties, the worst of his career, will hopefully see positive regression. This was the only time he’s been under 129 wRC+ since his 113 wRC+ rookie season.
In sum, the Rays could benefit from another right handed bat, but best chance to improve is by seeing better results from bats are already on the team.