He also can play 7 positions. OK, not as well as other options, but that flexibility is helpful
This is how I see the depth chart:
C - Vaz, Leon, Swihart
1B - Hanley, Moreland, Holt/Swihart
2B - Pedroia, Nunez, (Lin), Holt, Swihart
3B - Devers, Nunez, Holt, Swihart/(Lin)
SS - X, (Lin), Holt/Nunez
LF - Beni, Martinez, Holt/Swihart
CF - JBJ, Beni, Betts, (Lin), Holt
RF - Betts, JBJ, Martinez, Holt/Swihart
In my opinion, the value of his positional flexibility is negated by the fact that, even with both middle infielders currently on the DL, he should really only see the field at SS, 3B, and maybe LF. I'd rather see Swihart get the LF ABs whenever possible. This leaves out the other potential options of Marrero and Hernandez, who would be better at SS/3B if available. If an OFer misses an extended period, JDM becomes the LF, with Hanley/Moreland at DH. If a 1B goes down, Travis comes up. Off the 40-man, AAA also includes DeJesus, Barfield, Castillo, and Tavarez who I'd expect to provide similar or greater performance at the positions Holt plays if the need arose. This isn't a team that will need a lot of PAs from PHs, catcher being the only starter where it would really make any sense. And Holt isn't a guy that inspires any more confidence than Vazquez (or even Leon). The fact that Holt can play a bunch of positions adequately doesn't mean he ever should. The problem is, that's where a lot of his value lies. If that's not utilized, he just isn't worth very much at all. Holt was useful when he was the top utility guy on teams where we had a DH who didn't play the field and holes/timeshares at 3B or LF, but none of those situations apply in 2018.