“In the ballpark” (“In the ball park,” also “In the same ballpark,” “In the right ballpark”)

 
 
Wiktionary: in the ballpark
Prepositional phrase
in the ballpark
1. (figuratively) In the same general vicinity (as); somewhat similar (to); typically construed with of.
 
(Oxford English Dictionary)
ballpark, n. and adj.
A notional region or area within which comparisons, approximations, etc., can be made; an accepted or expected range, esp. one within which an amount or estimate is likely to be correct. Frequently as in the (right) ballpark: approximately right, fairly accurate. Also in the (same) ballpark: approximately similar, in the same area or range.
1945   K. Patchen Mem. Shy Pornographer 101   ‘Miro complicates it simply because he doesn’t know how to handle his material.’ ‘But Arp does, I suppose.’ ‘Of course he does.’ ‘You’re way out in left field.’ ‘And you’re not even in the ball park.’
1953   Atomic Power Devel. & Private Enterprise (Hearings before U.S. Congress Joint Comm. on Atomic Energy) 230   We need the full-scale plant in order to find out if we are in the ball park economically.
1957   San Francisco Examiner 5 Aug. ii. 15/2   I thought I would start with a figure that we could plus or minus a billion or so and be within the ball park.
1962   Wall St. Jrnl. 19 June 8/6 (advt.)  Its speed, range, and over-the-weather altitude put it in the same ballpark with the big airline jets.
1968   San Francisco Examiner 8 Oct. 58/7   The figures I have indicate this pay-out is ‘in the ball park’.
1970   Observer 24 May 40/6   You guys all belong in the same ballpark.
1972   Sat. Rev. (U.S.) 13 May 59/2   We can save lives with adequately equipped ambulances and properly trained personnel. It may be 50,000 or 75,000, but a figure of 60,000 is in the right ball park.