Per John Blake on Twitter, the Rangers have placed first baseman Mitch Moreland in the disabled list because of the hamstring injury he suffered during last night's game.
To take his place on the 25 man roster, the Rangers have purchased the contract of Chris McGuiness from AAA Round Rock, and transferred Colby Lewis to the 60 day disabled list. The Lewis move is purely procedural and won't impact when he returns.
McGuiness is a 25 year old lefthanded hitting first baseman who was a 13th round draft pick of the Boston Red Sox out of the Citadel in 2009, and who came over to Texas in the Jarrod Saltalamacchia trade.
McGuiness was left unprotected in the Rule 5 Draft last offseason, and was selected by the Cleveland Indians, although he did not make their 25 man roster and thus was returned to Texas this year. McGuiness is hitting .275/.382/.477 on the season.
Tepid did a write-up on McGuiness over the offseason which you can read here.
Either McGuiness or Mike Olt was going to get the call if Moreland went on the d.l., and with Olt just recently having returned from the disabled list, I suspect the Rangers didn't want to thrust him immediately back into the majors.